servo: Merge #19973 - style: Rework how media feature changes are handled for XBL (from emilio:media-feature-change); r=xidorn

Bug: 1435939
Reviewed-by: xidorn
Source-Repo: https://github.com/servo/servo
Source-Revision: e57319a7345eded057555f55f801e5f2c413f5b9

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 6da4b2d236318d13aad4a8f4c1211f733901fa96

servo/components/style/gecko/generated/bindings.rs

@@ -18,6 +18,7 @@ use gecko_bindings::structs::mozilla::dom::CallerType;
 use gecko_bindings::structs::mozilla::AnonymousCounterStyle;
 use gecko_bindings::structs::mozilla::AtomArray;
 use gecko_bindings::structs::mozilla::MallocSizeOf;
+use gecko_bindings::structs::mozilla::ServoStyleSet;
 use gecko_bindings::structs::mozilla::OriginFlags;
 use gecko_bindings::structs::mozilla::UniquePtr;
 use gecko_bindings::structs::ServoRawOffsetArc;
@@ -25,6 +26,7 @@ use gecko_bindings::structs::nsIContent;
 use gecko_bindings::structs::nsIDocument;
 use gecko_bindings::structs::nsIDocument_DocumentTheme;
 use gecko_bindings::structs::nsSimpleContentList;
+use gecko_bindings::structs::MediumFeaturesChangedResult;
 use gecko_bindings::structs::RawGeckoAnimationPropertySegment;
 use gecko_bindings::structs::RawGeckoComputedTiming;
 use gecko_bindings::structs::RawGeckoCSSPropertyIDList;
@@ -2097,15 +2099,10 @@ extern "C" {
 }
 extern "C" {
     pub fn Servo_StyleSet_MediumFeaturesChanged(
-        set: RawServoStyleSetBorrowed,
-        viewport_units_used: *mut bool,
-    ) -> u8;
-}
-extern "C" {
-    pub fn Servo_StyleSet_SetDevice(
-        set: RawServoStyleSetBorrowed,
-        pres_context: RawGeckoPresContextOwned,
-    ) -> u8;
+        document_set: RawServoStyleSetBorrowed,
+        non_document_sets: *const nsTArray<*mut ServoStyleSet>,
+        may_affect_default_style: bool,
+    ) -> MediumFeaturesChangedResult;
 }
 extern "C" {
     pub fn Servo_StyleSet_CompatModeChanged(raw_data: RawServoStyleSetBorrowed);

servo/components/style/stylist.rs

@@ -1089,9 +1089,6 @@ impl Stylist {
     ///
     /// Also, the device that arrives here may need to take the viewport rules
     /// into account.
-    ///
-    /// For Gecko, this is called when XBL bindings are used by different
-    /// documents.
     pub fn set_device(
         &mut self,
         mut device: Device,
@@ -1119,14 +1116,22 @@ impl Stylist {
         }
 
         self.device = device;
-        self.media_features_change_changed_style(guards)
+        self.media_features_change_changed_style(guards, &self.device)
     }
 
     /// Returns whether, given a media feature change, any previously-applicable
-    /// style has become non-applicable, or vice-versa for each origin.
+    /// style has become non-applicable, or vice-versa for each origin, using
+    /// `device`.
+    ///
+    /// Passing `device` is needed because this is used for XBL in Gecko, which
+    /// can be stale in various ways, so we need to pass the device of the
+    /// document itself, which is what is kept up-to-date.
+    ///
+    /// Arguably XBL should use something more lightweight than a Stylist.
     pub fn media_features_change_changed_style(
         &self,
         guards: &StylesheetGuards,
+        device: &Device,
     ) -> OriginSet {
         debug!("Stylist::media_features_change_changed_style");
 
@@ -1145,7 +1150,7 @@ impl Stylist {
             let affected_changed = !origin_cascade_data.media_feature_affected_matches(
                 stylesheet,
                 guard,
-                &self.device,
+                device,
                 self.quirks_mode
             );
 

servo/ports/geckolib/glue.rs

@@ -120,7 +120,7 @@ use style::gecko_bindings::sugar::ownership::{HasSimpleFFI, Strong};
 use style::gecko_bindings::sugar::refptr::RefPtr;
 use style::gecko_properties;
 use style::invalidation::element::restyle_hints;
-use style::media_queries::{Device, MediaList, parse_media_query_list};
+use style::media_queries::{MediaList, parse_media_query_list};
 use style::parser::{Parse, ParserContext, self};
 use style::properties::{ComputedValues, DeclarationSource, Importance};
 use style::properties::{LonghandId, LonghandIdSet, PropertyDeclaration, PropertyDeclarationBlock, PropertyId};
@@ -1121,10 +1121,11 @@ pub extern "C" fn Servo_StyleSet_AppendStyleSheet(
 }
 
 #[no_mangle]
-pub extern "C" fn Servo_StyleSet_MediumFeaturesChanged(
-    raw_data: RawServoStyleSetBorrowed,
-    viewport_units_used: *mut bool,
-) -> u8 {
+pub unsafe extern "C" fn Servo_StyleSet_MediumFeaturesChanged(
+    document_set: RawServoStyleSetBorrowed,
+    non_document_sets: *const nsTArray<*mut structs::ServoStyleSet>,
+    may_affect_default_style: bool,
+) -> structs::MediumFeaturesChangedResult {
     let global_style_data = &*GLOBAL_STYLE_DATA;
     let guard = global_style_data.shared_lock.read();
 
@@ -1135,43 +1136,58 @@ pub extern "C" fn Servo_StyleSet_MediumFeaturesChanged(
     //
     // We need to ensure the default computed values are up to date though,
     // because those can influence the result of media query evaluation.
-    //
-    // FIXME(emilio, bug 1369984): do the computation conditionally, to do it
-    // less often.
-    let mut data = PerDocumentStyleData::from_ffi(raw_data).borrow_mut();
+    let mut document_data =
+        PerDocumentStyleData::from_ffi(document_set).borrow_mut();
 
-    unsafe {
-        *viewport_units_used = data.stylist.device().used_viewport_size();
+    if may_affect_default_style {
+        document_data.stylist.device_mut().reset_computed_values();
     }
-    data.stylist.device_mut().reset_computed_values();
     let guards = StylesheetGuards::same(&guard);
+
     let origins_in_which_rules_changed =
-        data.stylist.media_features_change_changed_style(&guards);
+        document_data.stylist.media_features_change_changed_style(
+            &guards,
+            document_data.stylist.device(),
+        );
 
-    // We'd like to return `OriginFlags` here, but bindgen bitfield enums don't
-    // work as return values with the Linux 32-bit ABI at the moment because
-    // they wrap the value in a struct, so for now just unwrap it.
-    OriginFlags::from(origins_in_which_rules_changed).0
-}
+    let affects_document_rules = !origins_in_which_rules_changed.is_empty();
+    if affects_document_rules {
+        document_data.stylist.force_stylesheet_origins_dirty(origins_in_which_rules_changed);
+    }
 
-#[no_mangle]
-pub extern "C" fn Servo_StyleSet_SetDevice(
-    raw_data: RawServoStyleSetBorrowed,
-    pres_context: RawGeckoPresContextOwned
-) -> u8 {
-    let global_style_data = &*GLOBAL_STYLE_DATA;
-    let guard = global_style_data.shared_lock.read();
+    let mut affects_non_document_rules = false;
+    for non_document_style_set in &**non_document_sets {
+        let non_document_data = &*(**non_document_style_set).mRawSet.mPtr;
+        let non_document_data =
+            mem::transmute::<&structs::RawServoStyleSet, &bindings::RawServoStyleSet>(non_document_data);
+        let mut non_document_data =
+            PerDocumentStyleData::from_ffi(non_document_data).borrow_mut();
 
-    let mut data = PerDocumentStyleData::from_ffi(raw_data).borrow_mut();
-    let device = Device::new(pres_context);
-    let guards = StylesheetGuards::same(&guard);
-    let origins_in_which_rules_changed =
-        data.stylist.set_device(device, &guards);
+        let origins_changed =
+            non_document_data.stylist.media_features_change_changed_style(
+                &guards,
+                document_data.stylist.device(),
+            );
+        if !origins_changed.is_empty() {
+            affects_non_document_rules = true;
+            // XBL stylesets are rebuilt entirely, so we need to mark them
+            // dirty from here instead of going through the stylist
+            // force_origin_dirty stuff, which would be useless.
+            //
+            // FIXME(emilio, bug 1436059): This is super-hacky, make XBL /
+            // Shadow DOM not use a style set at all.
+            (**non_document_style_set).mStylistState = structs::StylistState_StyleSheetsDirty;
+        }
+    }
 
-    // We'd like to return `OriginFlags` here, but bindgen bitfield enums don't
-    // work as return values with the Linux 32-bit ABI at the moment because
-    // they wrap the value in a struct, so for now just unwrap it.
-    OriginFlags::from(origins_in_which_rules_changed).0
+    let uses_viewport_units =
+        document_data.stylist.device().used_viewport_size();
+
+    structs::MediumFeaturesChangedResult {
+        mAffectsDocumentRules: affects_document_rules,
+        mAffectsNonDocumentRules: affects_non_document_rules,
+        mUsesViewportUnits: uses_viewport_units,
+    }
 }
 
 #[no_mangle]