Auto merge of #16968 - HeyZoos:stylist-accessors, r=emilio

Stylist accessors

<!-- Please describe your changes on the following line: -->
Add accessor methods for the `device` and `ruleset` fields in the `Stylist` struct.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #16857 (github issue number if applicable).
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- [X] There are tests for these changes

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components/layout_thread/lib.rs

@@ -462,7 +462,7 @@ impl LayoutThread {
         for stylesheet in &ua_stylesheets.user_or_user_agent_stylesheets {
             add_font_face_rules(stylesheet,
                                 &guard,
-                                &stylist.device,
+                                stylist.device(),
                                 &font_cache_thread,
                                 &ipc_font_cache_sender,
                                 &outstanding_web_fonts_counter);
@@ -795,10 +795,10 @@ impl LayoutThread {
 
         let rw_data = possibly_locked_rw_data.lock();
         let guard = stylesheet.shared_lock.read();
-        if stylesheet.is_effective_for_device(&self.stylist.device, &guard) {
+        if stylesheet.is_effective_for_device(self.stylist.device(), &guard) {
             add_font_face_rules(&*stylesheet,
                                 &guard,
-                                &self.stylist.device,
+                                self.stylist.device(),
                                 &self.font_cache_thread,
                                 &self.font_cache_sender,
                                 &self.outstanding_web_fonts);
@@ -1261,11 +1261,11 @@ impl LayoutThread {
         }
 
         if opts::get().dump_rule_tree {
-            layout_context.style_context.stylist.rule_tree.dump_stdout(&guards);
+            layout_context.style_context.stylist.rule_tree().dump_stdout(&guards);
         }
 
         // GC the rule tree if some heuristics are met.
-        unsafe { layout_context.style_context.stylist.rule_tree.maybe_gc(); }
+        unsafe { layout_context.style_context.stylist.rule_tree().maybe_gc(); }
 
         // Perform post-style recalculation layout passes.
         if let Some(mut root_flow) = self.root_flow.borrow().clone() {

components/style/animation.rs

@@ -476,7 +476,7 @@ fn compute_style_for_animation_step(context: &SharedStyleContext,
             };
 
             let computed =
-                properties::apply_declarations(&context.stylist.device,
+                properties::apply_declarations(context.stylist.device(),
                                                /* is_root = */ false,
                                                iter,
                                                previous_style,

components/style/context.rs

@@ -150,7 +150,7 @@ pub struct SharedStyleContext<'a> {
 impl<'a> SharedStyleContext<'a> {
     /// Return a suitable viewport size in order to be used for viewport units.
     pub fn viewport_size(&self) -> Size2D<Au> {
-        self.stylist.device.au_viewport_size()
+        self.stylist.device().au_viewport_size()
     }
 }
 

components/style/gecko/data.rs

@@ -95,7 +95,7 @@ impl PerDocumentStyleDataImpl {
     ///
     /// Implies also a stylesheet flush.
     pub fn reset_device(&mut self, guard: &SharedRwLockReadGuard) {
-        Arc::get_mut(&mut self.stylist.device).unwrap().reset();
+        Arc::get_mut(self.stylist.device_mut()).unwrap().reset();
         self.stylesheets.force_dirty();
         self.flush_stylesheets(guard);
     }
@@ -123,7 +123,7 @@ impl PerDocumentStyleDataImpl {
 
     /// Get the default computed values for this document.
     pub fn default_computed_values(&self) -> &Arc<ComputedValues> {
-        self.stylist.device.default_computed_values_arc()
+        self.stylist.device().default_computed_values_arc()
     }
 
     /// Clear the stylist.  This will be a no-op if the stylist is

components/style/matching.rs

@@ -223,7 +223,7 @@ trait PrivateMatchMethods: TElement {
 
         // Invoke the cascade algorithm.
         let values =
-            Arc::new(cascade(&shared_context.stylist.device,
+            Arc::new(cascade(shared_context.stylist.device(),
                              rule_node,
                              &shared_context.guards,
                              style_to_inherit_from,
@@ -350,7 +350,7 @@ trait PrivateMatchMethods: TElement {
                               -> Option<Arc<ComputedValues>> {
         let rule_node = &primary_style.rules;
         let without_transition_rules =
-            context.shared.stylist.rule_tree.remove_transition_rule_if_applicable(rule_node);
+            context.shared.stylist.rule_tree().remove_transition_rule_if_applicable(rule_node);
         if without_transition_rules == *rule_node {
             // We don't have transition rule in this case, so return None to let the caller
             // use the original ComputedValues.
@@ -698,7 +698,7 @@ pub trait MatchMethods : TElement {
                 // Handle animations here.
                 if let Some(animation_rule) = animation_rules.0 {
                     let animation_rule_node =
-                        context.shared.stylist.rule_tree
+                        context.shared.stylist.rule_tree()
                             .update_rule_at_level(CascadeLevel::Animations,
                                                   Some(&animation_rule),
                                                   &mut rules,
@@ -710,7 +710,7 @@ pub trait MatchMethods : TElement {
 
                 if let Some(animation_rule) = animation_rules.1 {
                     let animation_rule_node =
-                        context.shared.stylist.rule_tree
+                        context.shared.stylist.rule_tree()
                             .update_rule_at_level(CascadeLevel::Transitions,
                                                   Some(&animation_rule),
                                                   &mut rules,
@@ -763,7 +763,7 @@ pub trait MatchMethods : TElement {
         *relations = matching_context.relations;
 
         let primary_rule_node =
-            compute_rule_node::<Self>(&stylist.rule_tree,
+            compute_rule_node::<Self>(stylist.rule_tree(),
                                       &mut applicable_declarations,
                                       &context.shared.guards);
 
@@ -816,7 +816,7 @@ pub trait MatchMethods : TElement {
         // at us later in the closure.
         let stylist = &context.shared.stylist;
         let guards = &context.shared.guards;
-        let rule_tree = &stylist.rule_tree;
+        let rule_tree = stylist.rule_tree();
         let bloom_filter = context.thread_local.bloom_filter.filter();
 
         let mut matching_context =
@@ -982,7 +982,7 @@ pub trait MatchMethods : TElement {
             let mut replace_rule_node = |level: CascadeLevel,
                                          pdb: Option<&Arc<Locked<PropertyDeclarationBlock>>>,
                                          path: &mut StrongRuleNode| {
-                let new_node = context.shared.stylist.rule_tree
+                let new_node = context.shared.stylist.rule_tree()
                     .update_rule_at_level(level, pdb, path, &context.shared.guards);
                 if let Some(n) = new_node {
                     *path = n;
@@ -1138,7 +1138,7 @@ pub trait MatchMethods : TElement {
         let relevant_style = pseudo_style.unwrap_or(primary_style);
         let rule_node = &relevant_style.rules;
         let without_animation_rules =
-            shared_context.stylist.rule_tree.remove_animation_rules(rule_node);
+            shared_context.stylist.rule_tree().remove_animation_rules(rule_node);
         if without_animation_rules == *rule_node {
             // Note that unwrapping here is fine, because the style is
             // only incomplete during the styling process.

components/style/stylist.rs

@@ -86,7 +86,7 @@ pub struct Stylist {
     ///
     /// In both cases, the device is actually _owned_ by the Stylist, and it's
     /// only an `Arc` so we can implement `add_stylesheet` more idiomatically.
-    pub device: Arc<Device>,
+    device: Arc<Device>,
 
     /// Viewport constraints based on the current device.
     viewport_constraints: Option<ViewportConstraints>,
@@ -106,9 +106,7 @@ pub struct Stylist {
     element_map: PerPseudoElementSelectorMap,
 
     /// The rule tree, that stores the results of selector matching.
-    ///
+    rule_tree: RuleTree,
-    /// FIXME(emilio): Not `pub`!
-    pub rule_tree: RuleTree,
 
     /// The selector maps corresponding to a given pseudo-element
     /// (depending on the implementation)
@@ -1064,6 +1062,21 @@ impl Stylist {
                                      CascadeFlags::empty(),
                                      self.quirks_mode))
     }
+
+    /// Accessor for a shared reference to the device.
+    pub fn device(&self) -> &Device {
+        &self.device
+    }
+
+    /// Accessor for a mutable reference to the device.
+    pub fn device_mut(&mut self) -> &mut Arc<Device> {
+        &mut self.device
+    }
+
+    /// Accessor for a shared reference to the rule tree.
+    pub fn rule_tree(&self) -> &RuleTree {
+        &self.rule_tree
+    }
 }
 
 impl Drop for Stylist {

ports/geckolib/glue.rs

@@ -1592,7 +1592,7 @@ pub extern "C" fn Servo_MediaList_Matches(list: RawServoMediaListBorrowed,
                                           -> bool {
     let per_doc_data = PerDocumentStyleData::from_ffi(raw_data).borrow();
     read_locked_arc(list, |list: &MediaList| {
-        list.evaluate(&per_doc_data.stylist.device, per_doc_data.stylist.quirks_mode())
+        list.evaluate(per_doc_data.stylist.device(), per_doc_data.stylist.quirks_mode())
     })
 }
 
@@ -2290,7 +2290,7 @@ pub extern "C" fn Servo_GetComputedKeyframeValues(keyframes: RawGeckoKeyframeLis
 
     let mut context = Context {
         is_root_element: false,
-        device: &data.stylist.device,
+        device: data.stylist.device(),
         inherited_style: parent_style.unwrap_or(default_values),
         layout_parent_style: parent_style.unwrap_or(default_values),
         style: StyleBuilder::for_derived_style(&style),
@@ -2368,7 +2368,7 @@ pub extern "C" fn Servo_AnimationValue_Compute(declarations: RawServoDeclaration
     let metrics = get_metrics_provider_for_product();
     let mut context = Context {
         is_root_element: false,
-        device: &data.stylist.device,
+        device: data.stylist.device(),
         inherited_style: parent_style.unwrap_or(default_values),
         layout_parent_style: parent_style.unwrap_or(default_values),
         style: StyleBuilder::for_derived_style(&style),

tests/unit/style/stylist.rs

@@ -3,10 +3,13 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use cssparser::SourceLocation;
+use euclid::TypedSize2D;
 use html5ever::LocalName;
 use selectors::parser::LocalName as LocalNameSelector;
 use selectors::parser::Selector;
 use servo_atoms::Atom;
+use style::context::QuirksMode;
+use style::media_queries::{Device, MediaType};
 use style::properties::{PropertyDeclarationBlock, PropertyDeclaration};
 use style::properties::{longhands, Importance};
 use style::rule_tree::CascadeLevel;
@@ -15,7 +18,7 @@ use style::shared_lock::SharedRwLock;
 use style::stylearc::Arc;
 use style::stylesheets::StyleRule;
 use style::stylist;
-use style::stylist::{Rule, SelectorMap};
+use style::stylist::{Rule, SelectorMap, Stylist};
 use style::stylist::needs_revalidation;
 use style::thread_state;
 
@@ -218,3 +221,23 @@ fn test_get_universal_rules() {
 
     assert_eq!(decls.len(), 1, "{:?}", decls);
 }
+
+fn mock_stylist() -> Stylist {
+    let device = Device::new(MediaType::Screen, TypedSize2D::new(0f32, 0f32));
+    Stylist::new(device, QuirksMode::NoQuirks)
+}
+
+#[test]
+fn test_stylist_device_accessors() {
+    let stylist = mock_stylist();
+    assert_eq!(stylist.device().media_type(), MediaType::Screen);
+    let mut stylist_mut = mock_stylist();
+    assert_eq!(stylist_mut.device_mut().media_type(), MediaType::Screen);
+}
+
+#[test]
+fn test_stylist_rule_tree_accessors() {
+    let stylist = mock_stylist();
+    stylist.rule_tree();
+    stylist.rule_tree().root();
+}