Auto merge of #15924 - upsuper:bug1315601, r=heycam,Manishearth

Implement access to CSSMediaRule for stylo

This is the Servo part of [bug 1315601](https://bugzilla.mozilla.org/show_bug.cgi?id=1315601).

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5 files changed, 212 insertions, 5 deletions

diff --git a/components/style/gecko/arc_types.rs b/components/style/gecko/arc_types.rs
index 72f044c1c71..95eff643161 100644
--- a/components/style/gecko/arc_types.rs
+++ b/components/style/gecko/arc_types.rs
@@ -8,14 +8,16 @@
 
 #![allow(non_snake_case, missing_docs)]
 
+use gecko_bindings::bindings::{RawServoMediaList, RawServoMediaRule};
 use gecko_bindings::bindings::{RawServoStyleSheet, RawServoStyleRule, RawServoImportRule};
 use gecko_bindings::bindings::{ServoComputedValues, ServoCssRules};
 use gecko_bindings::structs::{RawServoAnimationValue, RawServoDeclarationBlock};
 use gecko_bindings::sugar::ownership::{HasArcFFI, HasFFI};
+use media_queries::MediaList;
 use parking_lot::RwLock;
 use properties::{ComputedValues, PropertyDeclarationBlock};
 use properties::animated_properties::AnimationValue;
-use stylesheets::{CssRules, Stylesheet, StyleRule, ImportRule};
+use stylesheets::{CssRules, Stylesheet, StyleRule, ImportRule, MediaRule};
 
 macro_rules! impl_arc_ffi {
     ($servo_type:ty => $gecko_type:ty [$addref:ident, $release:ident]) => {
@@ -56,3 +58,9 @@ impl_arc_ffi!(RwLock<ImportRule> => RawServoImportRule
 
 impl_arc_ffi!(AnimationValue => RawServoAnimationValue
               [Servo_AnimationValue_AddRef, Servo_AnimationValue_Release]);
+
+impl_arc_ffi!(RwLock<MediaList> => RawServoMediaList
+              [Servo_MediaList_AddRef, Servo_MediaList_Release]);
+
+impl_arc_ffi!(RwLock<MediaRule> => RawServoMediaRule
+              [Servo_MediaRule_AddRef, Servo_MediaRule_Release]);
diff --git a/components/style/gecko/media_queries.rs b/components/style/gecko/media_queries.rs
index 0a14c3447dc..47c904cbe0e 100644
--- a/components/style/gecko/media_queries.rs
+++ b/components/style/gecko/media_queries.rs
@@ -137,8 +137,15 @@ impl ToCss for Expression {
     }
 }
 
+impl PartialEq for Expression {
+    fn eq(&self, other: &Expression) -> bool {
+        self.feature.mName == other.feature.mName &&
+            self.value == other.value && self.range == other.range
+    }
+}
+
 /// A resolution.
-#[derive(Debug, Clone)]
+#[derive(PartialEq, Debug, Clone)]
 pub enum Resolution {
     /// Dots per inch.
     Dpi(CSSFloat),
@@ -200,7 +207,7 @@ unsafe fn string_from_ns_string_buffer(buffer: *const nsStringBuffer) -> String
 }
 
 /// A value found or expected in a media expression.
-#[derive(Debug, Clone)]
+#[derive(PartialEq, Debug, Clone)]
 pub enum MediaExpressionValue {
     /// A length.
     Length(specified::Length),
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index a4454c46039..2a92156fee4 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -4,6 +4,16 @@ pub use nsstring::{nsACString, nsAString, nsString};
 type nsACString_internal = nsACString;
 type nsAString_internal = nsAString;
 use gecko_bindings::structs::mozilla::css::URLValue;
+pub type RawServoMediaListStrong = ::gecko_bindings::sugar::ownership::Strong<RawServoMediaList>;
+pub type RawServoMediaListBorrowedOrNull<'a> = Option<&'a RawServoMediaList>;
+pub type RawServoMediaListBorrowed<'a> = &'a RawServoMediaList;
+enum RawServoMediaListVoid{ }
+pub struct RawServoMediaList(RawServoMediaListVoid);
+pub type RawServoMediaRuleStrong = ::gecko_bindings::sugar::ownership::Strong<RawServoMediaRule>;
+pub type RawServoMediaRuleBorrowedOrNull<'a> = Option<&'a RawServoMediaRule>;
+pub type RawServoMediaRuleBorrowed<'a> = &'a RawServoMediaRule;
+enum RawServoMediaRuleVoid{ }
+pub struct RawServoMediaRule(RawServoMediaRuleVoid);
 use gecko_bindings::structs::RawGeckoDocument;
 use gecko_bindings::structs::RawGeckoElement;
 use gecko_bindings::structs::RawGeckoKeyframeList;
@@ -287,12 +297,24 @@ extern "C" {
                                               RawServoDeclarationBlockBorrowed);
 }
 extern "C" {
+    pub fn Servo_MediaList_AddRef(ptr: RawServoMediaListBorrowed);
+}
+extern "C" {
+    pub fn Servo_MediaList_Release(ptr: RawServoMediaListBorrowed);
+}
+extern "C" {
     pub fn Servo_StyleRule_AddRef(ptr: RawServoStyleRuleBorrowed);
 }
 extern "C" {
     pub fn Servo_StyleRule_Release(ptr: RawServoStyleRuleBorrowed);
 }
 extern "C" {
+    pub fn Servo_MediaRule_AddRef(ptr: RawServoMediaRuleBorrowed);
+}
+extern "C" {
+    pub fn Servo_MediaRule_Release(ptr: RawServoMediaRuleBorrowed);
+}
+extern "C" {
     pub fn Servo_ImportRule_AddRef(ptr: RawServoImportRuleBorrowed);
 }
 extern "C" {
@@ -1329,6 +1351,11 @@ extern "C" {
      -> RawServoStyleRuleStrong;
 }
 extern "C" {
+    pub fn Servo_CssRules_GetMediaRuleAt(rules: ServoCssRulesBorrowed,
+                                         index: u32)
+     -> RawServoMediaRuleStrong;
+}
+extern "C" {
     pub fn Servo_CssRules_InsertRule(rules: ServoCssRulesBorrowed,
                                      sheet: RawServoStyleSheetBorrowed,
                                      rule: *const nsACString_internal,
@@ -1361,6 +1388,22 @@ extern "C" {
                                            result: *mut nsAString_internal);
 }
 extern "C" {
+    pub fn Servo_MediaRule_Debug(rule: RawServoMediaRuleBorrowed,
+                                 result: *mut nsACString_internal);
+}
+extern "C" {
+    pub fn Servo_MediaRule_GetMedia(rule: RawServoMediaRuleBorrowed)
+     -> RawServoMediaListStrong;
+}
+extern "C" {
+    pub fn Servo_MediaRule_GetRules(rule: RawServoMediaRuleBorrowed)
+     -> ServoCssRulesStrong;
+}
+extern "C" {
+    pub fn Servo_MediaRule_GetCssText(rule: RawServoMediaRuleBorrowed,
+                                      result: *mut nsAString_internal);
+}
+extern "C" {
     pub fn Servo_ParseProperty(property: *const nsACString_internal,
                                value: *const nsACString_internal,
                                base: *const nsACString_internal,
@@ -1585,6 +1628,34 @@ extern "C" {
                                                                      RawServoDeclarationBlockBorrowed);
 }
 extern "C" {
+    pub fn Servo_MediaList_GetText(list: RawServoMediaListBorrowed,
+                                   result: *mut nsAString_internal);
+}
+extern "C" {
+    pub fn Servo_MediaList_SetText(list: RawServoMediaListBorrowed,
+                                   text: *const nsACString_internal);
+}
+extern "C" {
+    pub fn Servo_MediaList_GetLength(list: RawServoMediaListBorrowed) -> u32;
+}
+extern "C" {
+    pub fn Servo_MediaList_GetMediumAt(list: RawServoMediaListBorrowed,
+                                       index: u32,
+                                       result: *mut nsAString_internal)
+     -> bool;
+}
+extern "C" {
+    pub fn Servo_MediaList_AppendMedium(list: RawServoMediaListBorrowed,
+                                        new_medium:
+                                            *const nsACString_internal);
+}
+extern "C" {
+    pub fn Servo_MediaList_DeleteMedium(list: RawServoMediaListBorrowed,
+                                        old_medium:
+                                            *const nsACString_internal)
+     -> bool;
+}
+extern "C" {
     pub fn Servo_CSSSupports2(name: *const nsACString_internal,
                               value: *const nsACString_internal) -> bool;
 }
diff --git a/components/style/media_queries.rs b/components/style/media_queries.rs
index 19a7fd41b39..fea6811ffc2 100644
--- a/components/style/media_queries.rs
+++ b/components/style/media_queries.rs
@@ -66,7 +66,7 @@ impl ToCss for Qualifier {
 /// A [media query][mq].
 ///
 /// [mq]: https://drafts.csswg.org/mediaqueries/
-#[derive(Clone, Debug)]
+#[derive(PartialEq, Clone, Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct MediaQuery {
     /// The qualifier for this query.
@@ -299,4 +299,37 @@ impl MediaList {
     pub fn is_empty(&self) -> bool {
         self.media_queries.is_empty()
     }
+
+    /// Append a new media query item to the media list.
+    /// https://drafts.csswg.org/cssom/#dom-medialist-appendmedium
+    ///
+    /// Returns true if added, false if fail to parse the medium string.
+    pub fn append_medium(&mut self, new_medium: &str) -> bool {
+        let mut parser = Parser::new(new_medium);
+        let new_query = match MediaQuery::parse(&mut parser) {
+            Ok(query) => query,
+            Err(_) => { return false; }
+        };
+        // This algorithm doesn't actually matches the current spec,
+        // but it matches the behavior of Gecko and Edge.
+        // See https://github.com/w3c/csswg-drafts/issues/697
+        self.media_queries.retain(|query| query != &new_query);
+        self.media_queries.push(new_query);
+        true
+    }
+
+    /// Delete a media query from the media list.
+    /// https://drafts.csswg.org/cssom/#dom-medialist-deletemedium
+    ///
+    /// Returns true if found and deleted, false otherwise.
+    pub fn delete_medium(&mut self, old_medium: &str) -> bool {
+        let mut parser = Parser::new(old_medium);
+        let old_query = match MediaQuery::parse(&mut parser) {
+            Ok(query) => query,
+            Err(_) => { return false; }
+        };
+        let old_len = self.media_queries.len();
+        self.media_queries.retain(|query| query != &old_query);
+        old_len != self.media_queries.len()
+    }
 }
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 1a3ee5ac9a9..ac51002a1aa 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -32,6 +32,8 @@ use style::gecko::wrapper::GeckoElement;
 use style::gecko_bindings::bindings;
 use style::gecko_bindings::bindings::{RawGeckoKeyframeListBorrowed, RawGeckoKeyframeListBorrowedMut};
 use style::gecko_bindings::bindings::{RawServoDeclarationBlockBorrowed, RawServoDeclarationBlockStrong};
+use style::gecko_bindings::bindings::{RawServoMediaListBorrowed, RawServoMediaListStrong};
+use style::gecko_bindings::bindings::{RawServoMediaRuleBorrowed, RawServoMediaRuleStrong};
 use style::gecko_bindings::bindings::{RawServoStyleRuleBorrowed, RawServoStyleRuleStrong};
 use style::gecko_bindings::bindings::{RawServoStyleSetBorrowed, RawServoStyleSetOwned};
 use style::gecko_bindings::bindings::{RawServoStyleSheetBorrowed, ServoComputedValuesBorrowed};
@@ -62,6 +64,7 @@ use style::gecko_bindings::sugar::ownership::{HasSimpleFFI, Strong};
 use style::gecko_bindings::sugar::refptr::{GeckoArcPrincipal, GeckoArcURI};
 use style::gecko_properties::{self, style_structs};
 use style::keyframes::KeyframesStepValue;
+use style::media_queries::{MediaList, parse_media_query_list};
 use style::parallel;
 use style::parser::{ParserContext, ParserContextExtraData};
 use style::properties::{ComputedValues, Importance, ParsedDeclaration};
@@ -72,7 +75,7 @@ use style::restyle_hints::{self, RestyleHint};
 use style::selector_parser::PseudoElementCascadeType;
 use style::sequential;
 use style::string_cache::Atom;
-use style::stylesheets::{CssRule, CssRules, Origin, Stylesheet, StyleRule, ImportRule};
+use style::stylesheets::{CssRule, CssRules, ImportRule, MediaRule, Origin, Stylesheet, StyleRule};
 use style::stylesheets::StylesheetLoader as StyleStylesheetLoader;
 use style::supports::parse_condition_or_declaration;
 use style::thread_state;
@@ -519,6 +522,18 @@ pub extern "C" fn Servo_CssRules_GetStyleRuleAt(rules: ServoCssRulesBorrowed, in
 }
 
 #[no_mangle]
+pub extern "C" fn Servo_CssRules_GetMediaRuleAt(rules: ServoCssRulesBorrowed, index: u32)
+                                                -> RawServoMediaRuleStrong {
+    let rules = RwLock::<CssRules>::as_arc(&rules).read();
+    match rules.0[index as usize] {
+        CssRule::Media(ref rule) => rule.clone().into_strong(),
+        _ => {
+            unreachable!("GetMediaRuleAt should only be called on a media rule");
+        }
+    }
+}
+
+#[no_mangle]
 pub extern "C" fn Servo_CssRules_InsertRule(rules: ServoCssRulesBorrowed, sheet: RawServoStyleSheetBorrowed,
                                             rule: *const nsACString, index: u32, nested: bool,
                                             rule_type: *mut u16) -> nsresult {
@@ -577,6 +592,31 @@ pub extern "C" fn Servo_StyleRule_GetSelectorText(rule: RawServoStyleRuleBorrowe
 }
 
 #[no_mangle]
+pub extern "C" fn Servo_MediaRule_Debug(rule: RawServoMediaRuleBorrowed, result: *mut nsACString) -> () {
+    let rule = RwLock::<MediaRule>::as_arc(&rule);
+    let result = unsafe { result.as_mut().unwrap() };
+    write!(result, "{:?}", *rule.read()).unwrap();
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaRule_GetMedia(rule: RawServoMediaRuleBorrowed) -> RawServoMediaListStrong {
+    let rule = RwLock::<MediaRule>::as_arc(&rule);
+    rule.read().media_queries.clone().into_strong()
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaRule_GetRules(rule: RawServoMediaRuleBorrowed) -> ServoCssRulesStrong {
+    let rule = RwLock::<MediaRule>::as_arc(&rule);
+    rule.read().rules.clone().into_strong()
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaRule_GetCssText(rule: RawServoMediaRuleBorrowed, result: *mut nsAString) -> () {
+    let rule = RwLock::<MediaRule>::as_arc(&rule);
+    rule.read().to_css(unsafe { result.as_mut().unwrap() }).unwrap();
+}
+
+#[no_mangle]
 pub extern "C" fn Servo_ComputedValues_GetForAnonymousBox(parent_style_or_null: ServoComputedValuesBorrowedOrNull,
                                                          pseudo_tag: *mut nsIAtom,
                                                          raw_data: RawServoStyleSetBorrowed)
@@ -880,6 +920,54 @@ pub extern "C" fn Servo_DeclarationBlock_RemovePropertyById(declarations: RawSer
     remove_property(declarations, get_property_id_from_nscsspropertyid!(property, ()))
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_MediaList_GetText(list: RawServoMediaListBorrowed, result: *mut nsAString) {
+    let list = RwLock::<MediaList>::as_arc(&list);
+    list.read().to_css(unsafe { result.as_mut().unwrap() }).unwrap();
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaList_SetText(list: RawServoMediaListBorrowed, text: *const nsACString) {
+    let list = RwLock::<MediaList>::as_arc(&list);
+    let text = unsafe { text.as_ref().unwrap().as_str_unchecked() };
+    let mut parser = Parser::new(&text);
+    *list.write() = parse_media_query_list(&mut parser);
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaList_GetLength(list: RawServoMediaListBorrowed) -> u32 {
+    let list = RwLock::<MediaList>::as_arc(&list);
+    list.read().media_queries.len() as u32
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaList_GetMediumAt(list: RawServoMediaListBorrowed, index: u32,
+                                              result: *mut nsAString) -> bool {
+    let list = RwLock::<MediaList>::as_arc(&list);
+    if let Some(media_query) = list.read().media_queries.get(index as usize) {
+        media_query.to_css(unsafe { result.as_mut().unwrap() }).unwrap();
+        true
+    } else {
+        false
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaList_AppendMedium(list: RawServoMediaListBorrowed,
+                                               new_medium: *const nsACString) {
+    let list = RwLock::<MediaList>::as_arc(&list);
+    let new_medium = unsafe { new_medium.as_ref().unwrap().as_str_unchecked() };
+    list.write().append_medium(new_medium);
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_MediaList_DeleteMedium(list: RawServoMediaListBorrowed,
+                                               old_medium: *const nsACString) -> bool {
+    let list = RwLock::<MediaList>::as_arc(&list);
+    let old_medium = unsafe { old_medium.as_ref().unwrap().as_str_unchecked() };
+    list.write().delete_medium(old_medium)
+}
+
 macro_rules! get_longhand_from_id {
     ($id:expr, $retval:expr) => {
         match PropertyId::from_nscsspropertyid($id) {