servo: Merge #14433 - Implement MediaList interface (from canaltinova:medialist); r=Manishearth

<!-- Please describe your changes on the following line: -->
Added MediaList interface and implemented `mediaText`, `length` and `index` attributes.
r? @Manishearth

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

<!-- Either: -->
- [x] There are tests for these changes

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

Source-Repo: https://github.com/servo/servo
Source-Revision: 106a538e7e2898902093a77307f004ab79a270d8

servo/components/script/dom/cssmediarule.rs

@@ -3,12 +3,14 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::Bindings::CSSMediaRuleBinding;
-use dom::bindings::js::Root;
-use dom::bindings::reflector::reflect_dom_object;
+use dom::bindings::codegen::Bindings::CSSMediaRuleBinding::CSSMediaRuleMethods;
+use dom::bindings::js::{JS, MutNullableHeap, Root};
+use dom::bindings::reflector::{Reflectable, reflect_dom_object};
 use dom::bindings::str::DOMString;
 use dom::cssgroupingrule::CSSGroupingRule;
 use dom::cssrule::SpecificCSSRule;
 use dom::cssstylesheet::CSSStyleSheet;
+use dom::medialist::MediaList;
 use dom::window::Window;
 use parking_lot::RwLock;
 use std::sync::Arc;
@@ -20,6 +22,7 @@ pub struct CSSMediaRule {
     cssrule: CSSGroupingRule,
     #[ignore_heap_size_of = "Arc"]
     mediarule: Arc<RwLock<MediaRule>>,
+    medialist: MutNullableHeap<JS<MediaList>>,
 }
 
 impl CSSMediaRule {
@@ -29,6 +32,7 @@ impl CSSMediaRule {
         CSSMediaRule {
             cssrule: CSSGroupingRule::new_inherited(parent_stylesheet, list),
             mediarule: mediarule,
+            medialist: MutNullableHeap::new(None),
         }
     }
 
@@ -39,6 +43,11 @@ impl CSSMediaRule {
                            window,
                            CSSMediaRuleBinding::Wrap)
     }
+
+    fn medialist(&self) -> Root<MediaList> {
+        self.medialist.or_init(|| MediaList::new(self.global().as_window(),
+                                                 self.mediarule.read().media_queries.clone()))
+    }
 }
 
 impl SpecificCSSRule for CSSMediaRule {
@@ -51,3 +60,10 @@ impl SpecificCSSRule for CSSMediaRule {
         self.mediarule.read().to_css_string().into()
     }
 }
+
+impl CSSMediaRuleMethods for CSSMediaRule {
+    // https://drafts.csswg.org/cssom/#dom-cssgroupingrule-media
+    fn Media(&self) -> Root<MediaList> {
+        self.medialist()
+    }
+}

servo/components/script/dom/medialist.rs

@@ -0,0 +1,122 @@
+/* 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 core::default::Default;
+use cssparser::Parser;
+use dom::bindings::codegen::Bindings::MediaListBinding;
+use dom::bindings::codegen::Bindings::MediaListBinding::MediaListMethods;
+use dom::bindings::js::Root;
+use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::bindings::str::DOMString;
+use dom::window::Window;
+use parking_lot::RwLock;
+use std::sync::Arc;
+use style::media_queries::{MediaQuery, parse_media_query_list};
+use style::media_queries::MediaList as StyleMediaList;
+use style_traits::ToCss;
+
+#[dom_struct]
+pub struct MediaList {
+    reflector_: Reflector,
+    #[ignore_heap_size_of = "Arc"]
+    media_queries: Arc<RwLock<StyleMediaList>>,
+}
+
+impl MediaList {
+    #[allow(unrooted_must_root)]
+    pub fn new_inherited(media_queries: Arc<RwLock<StyleMediaList>>) -> MediaList {
+        MediaList {
+            reflector_: Reflector::new(),
+            media_queries: media_queries,
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    pub fn new(window: &Window, media_queries: Arc<RwLock<StyleMediaList>>)
+        -> Root<MediaList> {
+        reflect_dom_object(box MediaList::new_inherited(media_queries),
+                           window,
+                           MediaListBinding::Wrap)
+    }
+
+}
+
+impl MediaListMethods for MediaList {
+    // https://drafts.csswg.org/cssom/#dom-medialist-mediatext
+    fn MediaText(&self) -> DOMString {
+        DOMString::from(self.media_queries.read().to_css_string())
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-medialist-mediatext
+    fn SetMediaText(&self, value: DOMString) {
+        let mut media_queries = self.media_queries.write();
+        // Step 2
+        if value.is_empty() {
+            // Step 1
+            *media_queries = StyleMediaList::default();
+            return;
+        }
+        // Step 3
+        let mut parser = Parser::new(&value);
+        *media_queries = parse_media_query_list(&mut parser);
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-medialist-length
+    fn Length(&self) -> u32 {
+        self.media_queries.read().media_queries.len() as u32
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-medialist-item
+    fn Item(&self, index: u32) -> Option<DOMString> {
+        self.media_queries.read().media_queries.get(index as usize)
+                                            .and_then(|query| {
+            let mut s = String::new();
+            query.to_css(&mut s).unwrap();
+            Some(DOMString::from_string(s))
+        })
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-medialist-item
+    fn IndexedGetter(&self, index: u32) -> Option<DOMString> {
+        self.Item(index)
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-medialist-appendmedium
+    fn AppendMedium(&self, medium: DOMString) {
+        // Step 1
+        let mut parser = Parser::new(&medium);
+        let m = MediaQuery::parse(&mut parser);
+        // Step 2
+        if let Err(_) = m {
+            return;
+        }
+        // Step 3
+        let m_serialized = m.clone().unwrap().to_css_string();
+        let any = self.media_queries.read().media_queries.iter()
+                                    .any(|q| m_serialized == q.to_css_string());
+        if any {
+            return;
+        }
+        // Step 4
+        self.media_queries.write().media_queries.push(m.unwrap());
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-medialist-deletemedium
+    fn DeleteMedium(&self, medium: DOMString) {
+        // Step 1
+        let mut parser = Parser::new(&medium);
+        let m = MediaQuery::parse(&mut parser);
+        // Step 2
+        if let Err(_) = m {
+            return;
+        }
+        // Step 3
+        let m_serialized = m.unwrap().to_css_string();
+        let mut media_list = self.media_queries.write();
+        let new_vec = media_list.media_queries.drain(..)
+                                .filter(|q| m_serialized != q.to_css_string())
+                                .collect();
+        media_list.media_queries = new_vec;
+    }
+}

servo/components/script/dom/mod.rs

@@ -368,6 +368,7 @@ pub mod imagedata;
 pub mod keyboardevent;
 pub mod location;
 pub mod mediaerror;
+pub mod medialist;
 pub mod mediaquerylist;
 pub mod messageevent;
 pub mod mimetype;

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

@@ -5,5 +5,5 @@
 // https://drafts.csswg.org/cssom/#the-cssmediarule-interface
 [Exposed=Window]
 interface CSSMediaRule : CSSGroupingRule {
-  // [SameObject, PutForwards=mediaText] readonly attribute MediaList media;
+  [SameObject, PutForwards=mediaText] readonly attribute MediaList media;
 };

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

@@ -0,0 +1,13 @@
+/* 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/. */
+
+// https://drafts.csswg.org/cssom/#the-medialist-interface
+// [LegacyArrayClass]
+interface MediaList {
+  [TreatNullAs=EmptyString] /* stringifier */ attribute DOMString mediaText;
+  readonly attribute unsigned long length;
+  getter DOMString? item(unsigned long index);
+  void appendMedium(DOMString medium);
+  void deleteMedium(DOMString medium);
+};

servo/components/style/media_queries.rs

@@ -85,7 +85,7 @@ pub enum Qualifier {
     Not,
 }
 
-#[derive(Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct MediaQuery {
     pub qualifier: Option<Qualifier>,
@@ -206,7 +206,7 @@ impl Expression {
 }
 
 impl MediaQuery {
-    fn parse(input: &mut Parser) -> Result<MediaQuery, ()> {
+    pub fn parse(input: &mut Parser) -> Result<MediaQuery, ()> {
         let mut expressions = vec![];
 
         let qualifier = if input.try(|input| input.expect_ident_matching("only")).is_ok() {