stylo: Optimize some FFI calls

components/style/build_gecko.rs

@@ -235,6 +235,7 @@ mod bindings {
             .include(add_include("mozilla/Keyframe.h"))
             .include(add_include("mozilla/ServoElementSnapshot.h"))
             .include(add_include("mozilla/dom/Element.h"))
+            .include(add_include("mozilla/dom/NameSpaceConstants.h"))
             .include(add_include("mozilla/ServoBindings.h"))
             .include(add_include("nsMediaFeatures.h"))
             .include(add_include("nsMediaList.h"))
@@ -258,6 +259,7 @@ mod bindings {
             "BORDER_COLOR_.*",
             "BORDER_STYLE_.*",
             "mozilla::SERVO_PREF_.*",
+            "kNameSpaceID_.*",
         ];
         let whitelist = [
             "RawGecko.*",

components/style/gecko/wrapper.rs

@@ -25,12 +25,12 @@ use gecko::snapshot_helpers;
 use gecko_bindings::bindings;
 use gecko_bindings::bindings::{Gecko_DropStyleChildrenIterator, Gecko_MaybeCreateStyleChildrenIterator};
 use gecko_bindings::bindings::{Gecko_ElementState, Gecko_GetLastChild, Gecko_GetNextStyleChild};
-use gecko_bindings::bindings::{Gecko_GetServoDeclarationBlock, Gecko_IsHTMLElementInHTMLDocument};
 use gecko_bindings::bindings::{Gecko_IsLink, Gecko_IsRootElement, Gecko_MatchesElement};
 use gecko_bindings::bindings::{Gecko_IsUnvisitedLink, Gecko_IsVisitedLink, Gecko_Namespace};
 use gecko_bindings::bindings::{Gecko_SetNodeFlags, Gecko_UnsetNodeFlags};
 use gecko_bindings::bindings::Gecko_ClassOrClassList;
 use gecko_bindings::bindings::Gecko_GetAnimationRule;
+use gecko_bindings::bindings::Gecko_GetServoDeclarationBlock;
 use gecko_bindings::bindings::Gecko_GetStyleContext;
 use gecko_bindings::structs;
 use gecko_bindings::structs::{RawGeckoElement, RawGeckoNode};
@@ -83,11 +83,20 @@ impl<'ln> GeckoNode<'ln> {
         GeckoNode(&content._base)
     }
 
+    fn flags(&self) -> u32 {
+        (self.0)._base._base_1.mFlags
+    }
+
     fn node_info(&self) -> &structs::NodeInfo {
         debug_assert!(!self.0.mNodeInfo.mRawPtr.is_null());
         unsafe { &*self.0.mNodeInfo.mRawPtr }
     }
 
+    fn owner_doc(&self) -> &structs::nsIDocument {
+        debug_assert!(!self.node_info().mDocument.is_null());
+        unsafe { &*self.node_info().mDocument }
+    }
+
     fn first_child(&self) -> Option<GeckoNode<'ln>> {
         unsafe { self.0.mFirstChild.as_ref().map(GeckoNode::from_content) }
     }
@@ -103,6 +112,32 @@ impl<'ln> GeckoNode<'ln> {
     fn next_sibling(&self) -> Option<GeckoNode<'ln>> {
         unsafe { self.0.mNextSibling.as_ref().map(GeckoNode::from_content) }
     }
+
+    /// WARNING: This logic is duplicated in Gecko's FlattenedTreeParentIsParent.
+    /// Make sure to mirror any modifications in both places.
+    fn flattened_tree_parent_is_parent(&self) -> bool {
+        use ::gecko_bindings::structs::*;
+        let flags = self.flags();
+        if flags & (NODE_MAY_BE_IN_BINDING_MNGR as u32 |
+                    NODE_IS_IN_SHADOW_TREE as u32) != 0 {
+            return false;
+        }
+
+        let parent = unsafe { self.0.mParent.as_ref() }.map(GeckoNode);
+        let parent_el = parent.and_then(|p| p.as_element());
+        if flags & (NODE_IS_NATIVE_ANONYMOUS_ROOT as u32) != 0 &&
+           parent_el.map_or(false, |el| el.is_root())
+        {
+            return false;
+        }
+
+        if parent_el.map_or(false, |el| el.has_shadow_root()) {
+            return false;
+        }
+
+        true
+    }
+
 }
 
 impl<'ln> NodeInfo for GeckoNode<'ln> {
@@ -168,7 +203,13 @@ impl<'ln> TNode for GeckoNode<'ln> {
     }
 
     fn parent_node(&self) -> Option<Self> {
-        unsafe { bindings::Gecko_GetParentNode(self.0).map(GeckoNode) }
+        let fast_path = self.flattened_tree_parent_is_parent();
+        debug_assert!(fast_path == unsafe { bindings::Gecko_FlattenedTreeParentIsParent(self.0) });
+        if fast_path {
+            unsafe { self.0.mParent.as_ref().map(GeckoNode) }
+        } else {
+            unsafe { bindings::Gecko_GetParentNode(self.0).map(GeckoNode) }
+        }
     }
 
     fn is_in_doc(&self) -> bool {
@@ -278,6 +319,17 @@ impl<'le> GeckoElement<'le> {
         unsafe { Gecko_UnsetNodeFlags(self.as_node().0, flags) }
     }
 
+    /// Returns true if this element has a shadow root.
+    fn has_shadow_root(&self) -> bool {
+        self.get_dom_slots().map_or(false, |slots| !slots.mShadowRoot.mRawPtr.is_null())
+    }
+
+    /// Returns a reference to the DOM slots for this Element, if they exist.
+    fn get_dom_slots(&self) -> Option<&structs::FragmentOrElement_nsDOMSlots> {
+        let slots = self.as_node().0.mSlots as *const structs::FragmentOrElement_nsDOMSlots;
+        unsafe { slots.as_ref() }
+    }
+
     /// Clear the element data for a given element.
     pub fn clear_data(&self) {
         let ptr = self.0.mServoData.get();
@@ -440,7 +492,8 @@ impl<'le> PresentationalHintsSynthetizer for GeckoElement<'le> {
 
 impl<'le> ::selectors::Element for GeckoElement<'le> {
     fn parent_element(&self) -> Option<Self> {
-        unsafe { bindings::Gecko_GetParentElement(self.0).map(GeckoElement) }
+        let parent_node = self.as_node().parent_node();
+        parent_node.and_then(|n| n.as_element())
     }
 
     fn first_child_element(&self) -> Option<Self> {
@@ -565,9 +618,10 @@ impl<'le> ::selectors::Element for GeckoElement<'le> {
     }
 
     fn is_html_element_in_html_document(&self) -> bool {
-        unsafe {
-            Gecko_IsHTMLElementInHTMLDocument(self.0)
-        }
+        let node = self.as_node();
+        let node_info = node.node_info();
+        node_info.mInner.mNamespaceID == (structs::root::kNameSpaceID_XHTML as i32) &&
+        node.owner_doc().mType == structs::root::nsIDocument_Type::eHTML
     }
 }
 

components/style/gecko_bindings/bindings.rs

@@ -311,6 +311,10 @@ extern "C" {
 extern "C" {
     pub fn Gecko_IsInDocument(node: RawGeckoNodeBorrowed) -> bool;
 }
+extern "C" {
+    pub fn Gecko_FlattenedTreeParentIsParent(node: RawGeckoNodeBorrowed)
+     -> bool;
+}
 extern "C" {
     pub fn Gecko_GetParentNode(node: RawGeckoNodeBorrowed)
      -> RawGeckoNodeBorrowedOrNull;
@@ -331,10 +335,6 @@ extern "C" {
     pub fn Gecko_GetNextSibling(node: RawGeckoNodeBorrowed)
      -> RawGeckoNodeBorrowedOrNull;
 }
-extern "C" {
-    pub fn Gecko_GetParentElement(element: RawGeckoElementBorrowed)
-     -> RawGeckoElementBorrowedOrNull;
-}
 extern "C" {
     pub fn Gecko_GetFirstChildElement(element: RawGeckoElementBorrowed)
      -> RawGeckoElementBorrowedOrNull;
@@ -376,10 +376,6 @@ extern "C" {
 extern "C" {
     pub fn Gecko_ElementState(element: RawGeckoElementBorrowed) -> u16;
 }
-extern "C" {
-    pub fn Gecko_IsHTMLElementInHTMLDocument(element: RawGeckoElementBorrowed)
-     -> bool;
-}
 extern "C" {
     pub fn Gecko_IsLink(element: RawGeckoElementBorrowed) -> bool;
 }