style: Move author-style-disabled handling to push_applicable_declarations.

This will make it easier to handle it properly for Shadow DOM, though this patch
doesn't do that.

This also makes some method inline and infallible for convenience, since nobody
checks the errors anyway.

Bug: 1436798
Reviewed-by: bholley
MozReview-Commit-ID: Hq3erAUs5tf

3 files changed, 34 insertions, 49 deletions

diff --git a/components/style/stylesheet_set.rs b/components/style/stylesheet_set.rs
index 0277842262e..eeb75e738e6 100644
--- a/components/style/stylesheet_set.rs
+++ b/components/style/stylesheet_set.rs
@@ -124,16 +124,6 @@ impl Default for DataValidity {
     }
 }
 
-/// Whether author styles are enabled.
-///
-/// This is used to support Gecko.
-#[allow(missing_docs)]
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum AuthorStylesEnabled {
-    Yes,
-    No,
-}
-
 /// A struct to iterate over the different stylesheets to be flushed.
 pub struct StylesheetFlusher<'a, S>
 where
@@ -142,7 +132,6 @@ where
     origins_dirty: OriginSet,
     collections: &'a mut PerOrigin<SheetCollection<S>>,
     origin_data_validity: PerOrigin<DataValidity>,
-    author_styles_enabled: AuthorStylesEnabled,
     had_invalidations: bool,
 }
 
@@ -209,14 +198,6 @@ where
             "origin_data_validity should be a subset of origins_dirty!"
         );
 
-        if self.author_styles_enabled == AuthorStylesEnabled::No &&
-            origin == Origin::Author
-        {
-            return PerOriginFlusher {
-                iter: [].iter_mut(),
-                validity,
-            }
-        }
         PerOriginFlusher {
             iter: self.collections.borrow_mut_for_origin(&origin).entries.iter_mut(),
             validity,
@@ -411,9 +392,6 @@ where
 
     /// The invalidations for stylesheets added or removed from this document.
     invalidations: StylesheetInvalidationSet,
-
-    /// Whether author styles are enabled.
-    author_styles_enabled: AuthorStylesEnabled,
 }
 
 impl<S> DocumentStylesheetSet<S>
@@ -425,7 +403,6 @@ where
         Self {
             collections: Default::default(),
             invalidations: StylesheetInvalidationSet::new(),
-            author_styles_enabled: AuthorStylesEnabled::Yes,
         }
     }
 
@@ -510,18 +487,6 @@ where
         self.collections.borrow_mut_for_origin(&origin).remove(&sheet)
     }
 
-    /// Notes that the author style has been disabled for this document.
-    pub fn set_author_styles_enabled(&mut self, enabled: AuthorStylesEnabled) {
-        debug!("DocumentStylesheetSet::set_author_styles_enabled");
-        if self.author_styles_enabled == enabled {
-            return;
-        }
-        self.author_styles_enabled = enabled;
-        self.invalidations.invalidate_fully();
-        self.collections.borrow_mut_for_origin(&Origin::Author)
-            .set_data_validity_at_least(DataValidity::FullyInvalid)
-    }
-
     /// Returns whether the given set has changed from the last flush.
     pub fn has_changed(&self) -> bool {
         self.collections.iter_origins().any(|(collection, _)| collection.dirty)
@@ -560,7 +525,6 @@ where
 
         StylesheetFlusher {
             collections: &mut self.collections,
-            author_styles_enabled: self.author_styles_enabled,
             had_invalidations,
             origins_dirty,
             origin_data_validity,
diff --git a/components/style/stylist.rs b/components/style/stylist.rs
index 160c70df673..f656f77476b 100644
--- a/components/style/stylist.rs
+++ b/components/style/stylist.rs
@@ -41,7 +41,7 @@ use smallvec::SmallVec;
 use std::ops;
 use std::sync::Mutex;
 use style_traits::viewport::ViewportConstraints;
-use stylesheet_set::{AuthorStylesEnabled, DataValidity, SheetRebuildKind, DocumentStylesheetSet, StylesheetFlusher};
+use stylesheet_set::{DataValidity, SheetRebuildKind, DocumentStylesheetSet, StylesheetFlusher};
 #[cfg(feature = "gecko")]
 use stylesheets::{CounterStyleRule, FontFaceRule, FontFeatureValuesRule, PageRule};
 use stylesheets::{CssRule, Origin, OriginSet, PerOrigin, PerOriginIter};
@@ -332,6 +332,16 @@ impl DocumentCascadeData {
     }
 }
 
+/// Whether author styles are enabled.
+///
+/// This is used to support Gecko.
+#[allow(missing_docs)]
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq)]
+pub enum AuthorStylesEnabled {
+    Yes,
+    No,
+}
+
 /// A wrapper over a DocumentStylesheetSet that can be `Sync`, since it's only
 /// used and exposed via mutable methods in the `Stylist`.
 #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
@@ -397,6 +407,9 @@ pub struct Stylist {
     /// cascade level.
     cascade_data: DocumentCascadeData,
 
+    /// Whether author styles are enabled.
+    author_styles_enabled: AuthorStylesEnabled,
+
     /// The rule tree, that stores the results of selector matching.
     rule_tree: RuleTree,
 
@@ -437,6 +450,7 @@ impl Stylist {
             quirks_mode,
             stylesheets: StylistStylesheetSet::new(),
             cascade_data: Default::default(),
+            author_styles_enabled: AuthorStylesEnabled::Yes,
             rule_tree: RuleTree::new(),
             num_rebuilds: 0,
         }
@@ -593,7 +607,7 @@ impl Stylist {
 
     /// Sets whether author style is enabled or not.
     pub fn set_author_styles_enabled(&mut self, enabled: AuthorStylesEnabled) {
-        self.stylesheets.set_author_styles_enabled(enabled);
+        self.author_styles_enabled = enabled;
     }
 
     /// Returns whether we've recorded any stylesheet change so far.
@@ -1221,8 +1235,11 @@ impl Stylist {
 
         let only_default_rules =
             rule_inclusion == RuleInclusion::DefaultOnly;
-        let matches_user_and_author_rules =
+        let matches_user_rules =
             rule_hash_target.matches_user_and_author_rules();
+        let matches_author_rules =
+            matches_user_rules &&
+            self.author_styles_enabled == AuthorStylesEnabled::Yes;
 
         // Step 1: Normal user-agent rules.
         if let Some(map) = self.cascade_data.user_agent.cascade_data.normal_rules(pseudo_element) {
@@ -1260,7 +1277,7 @@ impl Stylist {
         //      rule_hash_target.matches_user_and_author_rules())
         //
         // Which may be more what you would probably expect.
-        if matches_user_and_author_rules {
+        if matches_user_rules {
             // Step 3a: User normal rules.
             if let Some(map) = self.cascade_data.user.normal_rules(pseudo_element) {
                 map.get_all_matching_rules(
@@ -1280,7 +1297,7 @@ impl Stylist {
         // particular, normally document rules override ::slotted() rules, but
         // for !important it should be the other way around. So probably we need
         // to add some sort of AuthorScoped cascade level or something.
-        if !only_default_rules {
+        if matches_author_rules && !only_default_rules {
             // Match slotted rules in reverse order, so that the outer slotted
             // rules come before the inner rules (and thus have less priority).
             let mut slots = SmallVec::<[_; 3]>::new();
@@ -1308,9 +1325,9 @@ impl Stylist {
 
         // FIXME(emilio): It looks very wrong to match XBL / Shadow DOM rules
         // even for getDefaultComputedStyle!
+        //
+        // Also, this doesn't account for the author_styles_enabled stuff.
         let cut_off_inheritance = element.each_xbl_stylist(|stylist| {
-            // ServoStyleSet::CreateXBLServoStyleSet() loads XBL style sheets
-            // under eAuthorSheetFeatures level.
             if let Some(map) = stylist.cascade_data.author.normal_rules(pseudo_element) {
                 // NOTE(emilio): This is needed because the XBL stylist may
                 // think it has a different quirks mode than the document.
@@ -1337,9 +1354,7 @@ impl Stylist {
             }
         });
 
-        if matches_user_and_author_rules && !only_default_rules &&
-            !cut_off_inheritance
-        {
+        if matches_author_rules && !only_default_rules && !cut_off_inheritance {
             // Step 3c: Author normal rules.
             if let Some(map) = self.cascade_data.author.normal_rules(pseudo_element) {
                 map.get_all_matching_rules(
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 94a46e3395f..fe46a215188 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -135,7 +135,6 @@ use style::selector_parser::{PseudoElementCascadeType, SelectorImpl};
 use style::shared_lock::{SharedRwLockReadGuard, StylesheetGuards, ToCssWithGuard, Locked};
 use style::string_cache::{Atom, WeakAtom};
 use style::style_adjuster::StyleAdjuster;
-use style::stylesheet_set::AuthorStylesEnabled;
 use style::stylesheets::{CssRule, CssRules, CssRuleType, CssRulesHelpers, DocumentRule};
 use style::stylesheets::{FontFeatureValuesRule, ImportRule, KeyframesRule, MediaRule};
 use style::stylesheets::{NamespaceRule, Origin, OriginSet, PageRule, StyleRule};
@@ -143,7 +142,7 @@ use style::stylesheets::{StylesheetContents, SupportsRule};
 use style::stylesheets::StylesheetLoader as StyleStylesheetLoader;
 use style::stylesheets::keyframes_rule::{Keyframe, KeyframeSelector, KeyframesStepValue};
 use style::stylesheets::supports_rule::parse_condition_or_declaration;
-use style::stylist::{add_size_of_ua_cache, RuleInclusion, Stylist};
+use style::stylist::{add_size_of_ua_cache, AuthorStylesEnabled, RuleInclusion, Stylist};
 use style::thread_state;
 use style::timer::Timer;
 use style::traversal::DomTraversal;
@@ -1248,11 +1247,18 @@ pub unsafe extern "C" fn Servo_StyleSet_FlushStyleSheets(
 #[no_mangle]
 pub extern "C" fn Servo_StyleSet_NoteStyleSheetsChanged(
     raw_data: RawServoStyleSetBorrowed,
-    author_style_disabled: bool,
     changed_origins: OriginFlags,
 ) {
     let mut data = PerDocumentStyleData::from_ffi(raw_data).borrow_mut();
     data.stylist.force_stylesheet_origins_dirty(OriginSet::from(changed_origins));
+}
+
+#[no_mangle]
+pub extern "C" fn Servo_StyleSet_SetAuthorStyleDisabled(
+    raw_data: RawServoStyleSetBorrowed,
+    author_style_disabled: bool,
+) {
+    let mut data = PerDocumentStyleData::from_ffi(raw_data).borrow_mut();
     let enabled =
         if author_style_disabled {
             AuthorStylesEnabled::No