servo: Merge #14340 - implement StyleSheet.disabled (from heycam:sheet-disabled); r=Manishearth

<!-- Please describe your changes on the following line: -->

This implements the [CSSOM StyleSheet.disabled](https://drafts.csswg.org/cssom/#dom-stylesheet-disabled) IDL attribute.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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Source-Repo: https://github.com/servo/servo
Source-Revision: c1c3974fb2d8ca60f2837ccd7d2d3b345e440af8

servo/components/script/dom/cssstylesheet.rs

@@ -4,11 +4,13 @@
 
 use dom::bindings::codegen::Bindings::CSSStyleSheetBinding;
 use dom::bindings::codegen::Bindings::CSSStyleSheetBinding::CSSStyleSheetMethods;
+use dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
 use dom::bindings::error::{ErrorResult, Fallible};
 use dom::bindings::js::{JS, Root, MutNullableHeap};
 use dom::bindings::reflector::{reflect_dom_object, Reflectable};
 use dom::bindings::str::DOMString;
 use dom::cssrulelist::{CSSRuleList, RulesSource};
+use dom::element::Element;
 use dom::stylesheet::StyleSheet;
 use dom::window::Window;
 use std::sync::Arc;
@@ -17,27 +19,34 @@ use style::stylesheets::Stylesheet as StyleStyleSheet;
 #[dom_struct]
 pub struct CSSStyleSheet {
     stylesheet: StyleSheet,
+    owner: JS<Element>,
     rulelist: MutNullableHeap<JS<CSSRuleList>>,
     #[ignore_heap_size_of = "Arc"]
     style_stylesheet: Arc<StyleStyleSheet>,
 }
 
 impl CSSStyleSheet {
-    fn new_inherited(type_: DOMString, href: Option<DOMString>,
-                     title: Option<DOMString>, stylesheet: Arc<StyleStyleSheet>) -> CSSStyleSheet {
+    fn new_inherited(owner: &Element,
+                     type_: DOMString,
+                     href: Option<DOMString>,
+                     title: Option<DOMString>,
+                     stylesheet: Arc<StyleStyleSheet>) -> CSSStyleSheet {
         CSSStyleSheet {
             stylesheet: StyleSheet::new_inherited(type_, href, title),
+            owner: JS::from_ref(owner),
             rulelist: MutNullableHeap::new(None),
             style_stylesheet: stylesheet,
         }
     }
 
     #[allow(unrooted_must_root)]
-    pub fn new(window: &Window, type_: DOMString,
+    pub fn new(window: &Window,
+               owner: &Element,
+               type_: DOMString,
                href: Option<DOMString>,
                title: Option<DOMString>,
                stylesheet: Arc<StyleStyleSheet>) -> Root<CSSStyleSheet> {
-        reflect_dom_object(box CSSStyleSheet::new_inherited(type_, href, title, stylesheet),
+        reflect_dom_object(box CSSStyleSheet::new_inherited(owner, type_, href, title, stylesheet),
                            window,
                            CSSStyleSheetBinding::Wrap)
     }
@@ -48,6 +57,16 @@ impl CSSStyleSheet {
                                                   RulesSource::Rules(self.style_stylesheet
                                                                          .rules.clone())))
     }
+
+    pub fn disabled(&self) -> bool {
+        self.style_stylesheet.disabled()
+    }
+
+    pub fn set_disabled(&self, disabled: bool) {
+        if self.style_stylesheet.set_disabled(disabled) {
+            self.global().as_window().Document().invalidate_stylesheets();
+        }
+    }
 }
 
 impl CSSStyleSheetMethods for CSSStyleSheet {

servo/components/script/dom/htmllinkelement.rs

@@ -94,6 +94,7 @@ impl HTMLLinkElement {
         self.get_stylesheet().map(|sheet| {
             self.cssom_stylesheet.or_init(|| {
                 CSSStyleSheet::new(&window_from_node(self),
+                                   self.upcast::<Element>(),
                                    "text/css".into(),
                                    None, // todo handle location
                                    None, // todo handle title

servo/components/script/dom/htmlmetaelement.rs

@@ -63,6 +63,7 @@ impl HTMLMetaElement {
         self.get_stylesheet().map(|sheet| {
             self.cssom_stylesheet.or_init(|| {
                 CSSStyleSheet::new(&window_from_node(self),
+                                   self.upcast::<Element>(),
                                    "text/css".into(),
                                    None, // todo handle location
                                    None, // todo handle title
@@ -103,6 +104,7 @@ impl HTMLMetaElement {
                         // Viewport constraints are always recomputed on resize; they don't need to
                         // force all styles to be recomputed.
                         dirty_on_viewport_size_change: AtomicBool::new(false),
+                        disabled: AtomicBool::new(false),
                     }));
                     let doc = document_from_node(self);
                     doc.invalidate_stylesheets();

servo/components/script/dom/htmlstyleelement.rs

@@ -86,6 +86,7 @@ impl HTMLStyleElement {
         self.get_stylesheet().map(|sheet| {
             self.cssom_stylesheet.or_init(|| {
                 CSSStyleSheet::new(&window_from_node(self),
+                                   self.upcast::<Element>(),
                                    "text/css".into(),
                                    None, // todo handle location
                                    None, // todo handle title

servo/components/script/dom/stylesheet.rs

@@ -4,12 +4,13 @@
 
 use dom::bindings::codegen::Bindings::StyleSheetBinding;
 use dom::bindings::codegen::Bindings::StyleSheetBinding::StyleSheetMethods;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflector, reflect_dom_object};
 use dom::bindings::str::DOMString;
+use dom::cssstylesheet::CSSStyleSheet;
 use dom::window::Window;
 
-
 #[dom_struct]
 pub struct StyleSheet {
     reflector_: Reflector,
@@ -20,12 +21,14 @@ pub struct StyleSheet {
 
 impl StyleSheet {
     #[allow(unrooted_must_root)]
-    pub fn new_inherited(type_: DOMString, href: Option<DOMString>, title: Option<DOMString>) -> StyleSheet {
+    pub fn new_inherited(type_: DOMString,
+                         href: Option<DOMString>,
+                         title: Option<DOMString>) -> StyleSheet {
         StyleSheet {
             reflector_: Reflector::new(),
             type_: type_,
             href: href,
-            title: title
+            title: title,
         }
     }
 
@@ -55,5 +58,14 @@ impl StyleSheetMethods for StyleSheet {
     fn GetTitle(&self) -> Option<DOMString> {
         self.title.clone()
     }
-}
 
+    // https://drafts.csswg.org/cssom/#dom-stylesheet-disabled
+    fn Disabled(&self) -> bool {
+        self.downcast::<CSSStyleSheet>().unwrap().disabled()
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-stylesheet-disabled
+    fn SetDisabled(&self, disabled: bool) {
+        self.downcast::<CSSStyleSheet>().unwrap().set_disabled(disabled)
+    }
+}

servo/components/script/dom/webidls/StyleSheet.webidl

@@ -13,7 +13,7 @@ interface StyleSheet {
   readonly attribute DOMString? title;
 
   // [SameObject, PutForwards=mediaText] readonly attribute MediaList media;
-  // attribute boolean disabled;
+  attribute boolean disabled;
 };
 
 // https://drafts.csswg.org/cssom/#the-linkstyle-interface

servo/components/style/stylesheets.rs

@@ -113,6 +113,7 @@ pub struct Stylesheet {
     pub media: Arc<RwLock<MediaList>>,
     pub origin: Origin,
     pub dirty_on_viewport_size_change: AtomicBool,
+    pub disabled: AtomicBool,
 }
 
 
@@ -402,6 +403,7 @@ impl Stylesheet {
             rules: rules.into(),
             media: Arc::new(RwLock::new(media)),
             dirty_on_viewport_size_change: AtomicBool::new(input.seen_viewport_percentages()),
+            disabled: AtomicBool::new(false),
         }
     }
 
@@ -442,6 +444,20 @@ impl Stylesheet {
     pub fn effective_rules<F>(&self, device: &Device, mut f: F) where F: FnMut(&CssRule) {
         effective_rules(&self.rules.0.read(), device, &mut f);
     }
+
+    /// Returns whether the stylesheet has been explicitly disabled through the CSSOM.
+    pub fn disabled(&self) -> bool {
+        self.disabled.load(Ordering::SeqCst)
+    }
+
+    /// Records that the stylesheet has been explicitly disabled through the CSSOM.
+    /// Returns whether the the call resulted in a change in disabled state.
+    ///
+    /// Disabled stylesheets remain in the document, but their rules are not added to
+    /// the Stylist.
+    pub fn set_disabled(&self, disabled: bool) -> bool {
+        self.disabled.swap(disabled, Ordering::SeqCst) != disabled
+    }
 }
 
 fn effective_rules<F>(rules: &[CssRule], device: &Device, f: &mut F) where F: FnMut(&CssRule) {

servo/components/style/stylist.rs

@@ -169,7 +169,7 @@ impl Stylist {
     }
 
     fn add_stylesheet(&mut self, stylesheet: &Stylesheet) {
-        if !stylesheet.is_effective_for_device(&self.device) {
+        if stylesheet.disabled() || !stylesheet.is_effective_for_device(&self.device) {
             return;
         }
 

servo/tests/unit/style/stylesheets.rs

@@ -57,6 +57,7 @@ fn test_parse_stylesheet() {
         origin: Origin::UserAgent,
         media: Default::default(),
         dirty_on_viewport_size_change: AtomicBool::new(false),
+        disabled: AtomicBool::new(false),
         rules: vec![
             CssRule::Namespace(Arc::new(RwLock::new(NamespaceRule {
                 prefix: None,