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| -rw-r--r-- | servo/components/style/dom.rs | 947 |
1 files changed, 947 insertions, 0 deletions
diff --git a/servo/components/style/dom.rs b/servo/components/style/dom.rs new file mode 100644 index 0000000000..cffc24f6cc --- /dev/null +++ b/servo/components/style/dom.rs @@ -0,0 +1,947 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ + +//! Types and traits used to access the DOM from style calculation. + +#![allow(unsafe_code)] +#![deny(missing_docs)] + +use crate::applicable_declarations::ApplicableDeclarationBlock; +use crate::context::SharedStyleContext; +#[cfg(feature = "gecko")] +use crate::context::{PostAnimationTasks, UpdateAnimationsTasks}; +use crate::data::ElementData; +use crate::media_queries::Device; +use crate::properties::{AnimationDeclarations, ComputedValues, PropertyDeclarationBlock}; +use crate::selector_parser::{AttrValue, Lang, PseudoElement, SelectorImpl}; +use crate::shared_lock::{Locked, SharedRwLock}; +use crate::stylist::CascadeData; +use crate::values::computed::Display; +use crate::values::AtomIdent; +use crate::{LocalName, Namespace, WeakAtom}; +use atomic_refcell::{AtomicRef, AtomicRefMut}; +use dom::ElementState; +use selectors::matching::{QuirksMode, VisitedHandlingMode}; +use selectors::sink::Push; +use selectors::Element as SelectorsElement; +use servo_arc::{Arc, ArcBorrow}; +use std::fmt; +use std::fmt::Debug; +use std::hash::Hash; +use std::ops::Deref; + +pub use style_traits::dom::OpaqueNode; + +/// Simple trait to provide basic information about the type of an element. +/// +/// We avoid exposing the full type id, since computing it in the general case +/// would be difficult for Gecko nodes. +pub trait NodeInfo { + /// Whether this node is an element. + fn is_element(&self) -> bool; + /// Whether this node is a text node. + fn is_text_node(&self) -> bool; +} + +/// A node iterator that only returns node that don't need layout. +pub struct LayoutIterator<T>(pub T); + +impl<T, N> Iterator for LayoutIterator<T> +where + T: Iterator<Item = N>, + N: NodeInfo, +{ + type Item = N; + + fn next(&mut self) -> Option<N> { + loop { + let n = self.0.next()?; + // Filter out nodes that layout should ignore. + if n.is_text_node() || n.is_element() { + return Some(n); + } + } + } +} + +/// An iterator over the DOM children of a node. +pub struct DomChildren<N>(Option<N>); +impl<N> Iterator for DomChildren<N> +where + N: TNode, +{ + type Item = N; + + fn next(&mut self) -> Option<N> { + let n = self.0.take()?; + self.0 = n.next_sibling(); + Some(n) + } +} + +/// An iterator over the DOM descendants of a node in pre-order. +pub struct DomDescendants<N> { + previous: Option<N>, + scope: N, +} + +impl<N> Iterator for DomDescendants<N> +where + N: TNode, +{ + type Item = N; + + #[inline] + fn next(&mut self) -> Option<N> { + let prev = self.previous.take()?; + self.previous = prev.next_in_preorder(self.scope); + self.previous + } +} + +/// The `TDocument` trait, to represent a document node. +pub trait TDocument: Sized + Copy + Clone { + /// The concrete `TNode` type. + type ConcreteNode: TNode<ConcreteDocument = Self>; + + /// Get this document as a `TNode`. + fn as_node(&self) -> Self::ConcreteNode; + + /// Returns whether this document is an HTML document. + fn is_html_document(&self) -> bool; + + /// Returns the quirks mode of this document. + fn quirks_mode(&self) -> QuirksMode; + + /// Get a list of elements with a given ID in this document, sorted by + /// tree position. + /// + /// Can return an error to signal that this list is not available, or also + /// return an empty slice. + fn elements_with_id<'a>( + &self, + _id: &AtomIdent, + ) -> Result<&'a [<Self::ConcreteNode as TNode>::ConcreteElement], ()> + where + Self: 'a, + { + Err(()) + } + + /// This document's shared lock. + fn shared_lock(&self) -> &SharedRwLock; +} + +/// The `TNode` trait. This is the main generic trait over which the style +/// system can be implemented. +pub trait TNode: Sized + Copy + Clone + Debug + NodeInfo + PartialEq { + /// The concrete `TElement` type. + type ConcreteElement: TElement<ConcreteNode = Self>; + + /// The concrete `TDocument` type. + type ConcreteDocument: TDocument<ConcreteNode = Self>; + + /// The concrete `TShadowRoot` type. + type ConcreteShadowRoot: TShadowRoot<ConcreteNode = Self>; + + /// Get this node's parent node. + fn parent_node(&self) -> Option<Self>; + + /// Get this node's first child. + fn first_child(&self) -> Option<Self>; + + /// Get this node's last child. + fn last_child(&self) -> Option<Self>; + + /// Get this node's previous sibling. + fn prev_sibling(&self) -> Option<Self>; + + /// Get this node's next sibling. + fn next_sibling(&self) -> Option<Self>; + + /// Get the owner document of this node. + fn owner_doc(&self) -> Self::ConcreteDocument; + + /// Iterate over the DOM children of a node. + #[inline(always)] + fn dom_children(&self) -> DomChildren<Self> { + DomChildren(self.first_child()) + } + + /// Returns whether the node is attached to a document. + fn is_in_document(&self) -> bool; + + /// Iterate over the DOM children of a node, in preorder. + #[inline(always)] + fn dom_descendants(&self) -> DomDescendants<Self> { + DomDescendants { + previous: Some(*self), + scope: *self, + } + } + + /// Returns the next node after this one, in a pre-order tree-traversal of + /// the subtree rooted at scoped_to. + #[inline] + fn next_in_preorder(&self, scoped_to: Self) -> Option<Self> { + if let Some(c) = self.first_child() { + return Some(c); + } + + let mut current = *self; + loop { + if current == scoped_to { + return None; + } + + if let Some(s) = current.next_sibling() { + return Some(s); + } + + debug_assert!( + current.parent_node().is_some(), + "Not a descendant of the scope?" + ); + current = current.parent_node()?; + } + } + + /// Get this node's parent element from the perspective of a restyle + /// traversal. + fn traversal_parent(&self) -> Option<Self::ConcreteElement>; + + /// Get this node's parent element if present. + fn parent_element(&self) -> Option<Self::ConcreteElement> { + self.parent_node().and_then(|n| n.as_element()) + } + + /// Get this node's parent element, or shadow host if it's a shadow root. + fn parent_element_or_host(&self) -> Option<Self::ConcreteElement> { + let parent = self.parent_node()?; + if let Some(e) = parent.as_element() { + return Some(e); + } + if let Some(root) = parent.as_shadow_root() { + return Some(root.host()); + } + None + } + + /// Converts self into an `OpaqueNode`. + fn opaque(&self) -> OpaqueNode; + + /// A debug id, only useful, mm... for debugging. + fn debug_id(self) -> usize; + + /// Get this node as an element, if it's one. + fn as_element(&self) -> Option<Self::ConcreteElement>; + + /// Get this node as a document, if it's one. + fn as_document(&self) -> Option<Self::ConcreteDocument>; + + /// Get this node as a ShadowRoot, if it's one. + fn as_shadow_root(&self) -> Option<Self::ConcreteShadowRoot>; +} + +/// Wrapper to output the subtree rather than the single node when formatting +/// for Debug. +pub struct ShowSubtree<N: TNode>(pub N); +impl<N: TNode> Debug for ShowSubtree<N> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + writeln!(f, "DOM Subtree:")?; + fmt_subtree(f, &|f, n| write!(f, "{:?}", n), self.0, 1) + } +} + +/// Wrapper to output the subtree along with the ElementData when formatting +/// for Debug. +pub struct ShowSubtreeData<N: TNode>(pub N); +impl<N: TNode> Debug for ShowSubtreeData<N> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + writeln!(f, "DOM Subtree:")?; + fmt_subtree(f, &|f, n| fmt_with_data(f, n), self.0, 1) + } +} + +/// Wrapper to output the subtree along with the ElementData and primary +/// ComputedValues when formatting for Debug. This is extremely verbose. +#[cfg(feature = "servo")] +pub struct ShowSubtreeDataAndPrimaryValues<N: TNode>(pub N); +#[cfg(feature = "servo")] +impl<N: TNode> Debug for ShowSubtreeDataAndPrimaryValues<N> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + writeln!(f, "DOM Subtree:")?; + fmt_subtree(f, &|f, n| fmt_with_data_and_primary_values(f, n), self.0, 1) + } +} + +fn fmt_with_data<N: TNode>(f: &mut fmt::Formatter, n: N) -> fmt::Result { + if let Some(el) = n.as_element() { + write!( + f, + "{:?} dd={} aodd={} data={:?}", + el, + el.has_dirty_descendants(), + el.has_animation_only_dirty_descendants(), + el.borrow_data(), + ) + } else { + write!(f, "{:?}", n) + } +} + +#[cfg(feature = "servo")] +fn fmt_with_data_and_primary_values<N: TNode>(f: &mut fmt::Formatter, n: N) -> fmt::Result { + if let Some(el) = n.as_element() { + let dd = el.has_dirty_descendants(); + let aodd = el.has_animation_only_dirty_descendants(); + let data = el.borrow_data(); + let values = data.as_ref().and_then(|d| d.styles.get_primary()); + write!( + f, + "{:?} dd={} aodd={} data={:?} values={:?}", + el, dd, aodd, &data, values + ) + } else { + write!(f, "{:?}", n) + } +} + +fn fmt_subtree<F, N: TNode>(f: &mut fmt::Formatter, stringify: &F, n: N, indent: u32) -> fmt::Result +where + F: Fn(&mut fmt::Formatter, N) -> fmt::Result, +{ + for _ in 0..indent { + write!(f, " ")?; + } + stringify(f, n)?; + if let Some(e) = n.as_element() { + for kid in e.traversal_children() { + writeln!(f, "")?; + fmt_subtree(f, stringify, kid, indent + 1)?; + } + } + + Ok(()) +} + +/// The ShadowRoot trait. +pub trait TShadowRoot: Sized + Copy + Clone + Debug + PartialEq { + /// The concrete node type. + type ConcreteNode: TNode<ConcreteShadowRoot = Self>; + + /// Get this ShadowRoot as a node. + fn as_node(&self) -> Self::ConcreteNode; + + /// Get the shadow host that hosts this ShadowRoot. + fn host(&self) -> <Self::ConcreteNode as TNode>::ConcreteElement; + + /// Get the style data for this ShadowRoot. + fn style_data<'a>(&self) -> Option<&'a CascadeData> + where + Self: 'a; + + /// Get the list of shadow parts for this shadow root. + fn parts<'a>(&self) -> &[<Self::ConcreteNode as TNode>::ConcreteElement] + where + Self: 'a, + { + &[] + } + + /// Get a list of elements with a given ID in this shadow root, sorted by + /// tree position. + /// + /// Can return an error to signal that this list is not available, or also + /// return an empty slice. + fn elements_with_id<'a>( + &self, + _id: &AtomIdent, + ) -> Result<&'a [<Self::ConcreteNode as TNode>::ConcreteElement], ()> + where + Self: 'a, + { + Err(()) + } +} + +/// The element trait, the main abstraction the style crate acts over. +pub trait TElement: + Eq + PartialEq + Debug + Hash + Sized + Copy + Clone + SelectorsElement<Impl = SelectorImpl> +{ + /// The concrete node type. + type ConcreteNode: TNode<ConcreteElement = Self>; + + /// A concrete children iterator type in order to iterate over the `Node`s. + /// + /// TODO(emilio): We should eventually replace this with the `impl Trait` + /// syntax. + type TraversalChildrenIterator: Iterator<Item = Self::ConcreteNode>; + + /// Get this element as a node. + fn as_node(&self) -> Self::ConcreteNode; + + /// A debug-only check that the device's owner doc matches the actual doc + /// we're the root of. + /// + /// Otherwise we may set document-level state incorrectly, like the root + /// font-size used for rem units. + fn owner_doc_matches_for_testing(&self, _: &Device) -> bool { + true + } + + /// Whether this element should match user and content rules. + /// + /// We use this for Native Anonymous Content in Gecko. + fn matches_user_and_content_rules(&self) -> bool { + true + } + + /// Returns the depth of this element in the DOM. + fn depth(&self) -> usize { + let mut depth = 0; + let mut curr = *self; + while let Some(parent) = curr.traversal_parent() { + depth += 1; + curr = parent; + } + + depth + } + + /// Get this node's parent element from the perspective of a restyle + /// traversal. + fn traversal_parent(&self) -> Option<Self> { + self.as_node().traversal_parent() + } + + /// Get this node's children from the perspective of a restyle traversal. + fn traversal_children(&self) -> LayoutIterator<Self::TraversalChildrenIterator>; + + /// Returns the parent element we should inherit from. + /// + /// This is pretty much always the parent element itself, except in the case + /// of Gecko's Native Anonymous Content, which uses the traversal parent + /// (i.e. the flattened tree parent) and which also may need to find the + /// closest non-NAC ancestor. + fn inheritance_parent(&self) -> Option<Self> { + self.parent_element() + } + + /// The ::before pseudo-element of this element, if it exists. + fn before_pseudo_element(&self) -> Option<Self> { + None + } + + /// The ::after pseudo-element of this element, if it exists. + fn after_pseudo_element(&self) -> Option<Self> { + None + } + + /// The ::marker pseudo-element of this element, if it exists. + fn marker_pseudo_element(&self) -> Option<Self> { + None + } + + /// Execute `f` for each anonymous content child (apart from ::before and + /// ::after) whose originating element is `self`. + fn each_anonymous_content_child<F>(&self, _f: F) + where + F: FnMut(Self), + { + } + + /// Return whether this element is an element in the HTML namespace. + fn is_html_element(&self) -> bool; + + /// Return whether this element is an element in the MathML namespace. + fn is_mathml_element(&self) -> bool; + + /// Return whether this element is an element in the SVG namespace. + fn is_svg_element(&self) -> bool; + + /// Return whether this element is an element in the XUL namespace. + fn is_xul_element(&self) -> bool { + false + } + + /// Return the list of slotted nodes of this node. + fn slotted_nodes(&self) -> &[Self::ConcreteNode] { + &[] + } + + /// Get this element's style attribute. + fn style_attribute(&self) -> Option<ArcBorrow<Locked<PropertyDeclarationBlock>>>; + + /// Unset the style attribute's dirty bit. + /// Servo doesn't need to manage ditry bit for style attribute. + fn unset_dirty_style_attribute(&self) {} + + /// Get this element's SMIL override declarations. + fn smil_override(&self) -> Option<ArcBorrow<Locked<PropertyDeclarationBlock>>> { + None + } + + /// Get the combined animation and transition rules. + /// + /// FIXME(emilio): Is this really useful? + fn animation_declarations(&self, context: &SharedStyleContext) -> AnimationDeclarations { + if !self.may_have_animations() { + return Default::default(); + } + + AnimationDeclarations { + animations: self.animation_rule(context), + transitions: self.transition_rule(context), + } + } + + /// Get this element's animation rule. + fn animation_rule( + &self, + _: &SharedStyleContext, + ) -> Option<Arc<Locked<PropertyDeclarationBlock>>>; + + /// Get this element's transition rule. + fn transition_rule( + &self, + context: &SharedStyleContext, + ) -> Option<Arc<Locked<PropertyDeclarationBlock>>>; + + /// Get this element's state, for non-tree-structural pseudos. + fn state(&self) -> ElementState; + + /// Whether this element has an attribute with a given namespace. + fn has_attr(&self, namespace: &Namespace, attr: &LocalName) -> bool; + + /// Returns whether this element has a `part` attribute. + fn has_part_attr(&self) -> bool; + + /// Returns whether this element exports any part from its shadow tree. + fn exports_any_part(&self) -> bool; + + /// The ID for this element. + fn id(&self) -> Option<&WeakAtom>; + + /// Internal iterator for the classes of this element. + fn each_class<F>(&self, callback: F) + where + F: FnMut(&AtomIdent); + + /// Internal iterator for the part names of this element. + fn each_part<F>(&self, _callback: F) + where + F: FnMut(&AtomIdent), + { + } + + /// Internal iterator for the attribute names of this element. + fn each_attr_name<F>(&self, callback: F) + where + F: FnMut(&AtomIdent); + + /// Internal iterator for the part names that this element exports for a + /// given part name. + fn each_exported_part<F>(&self, _name: &AtomIdent, _callback: F) + where + F: FnMut(&AtomIdent), + { + } + + /// Whether a given element may generate a pseudo-element. + /// + /// This is useful to avoid computing, for example, pseudo styles for + /// `::-first-line` or `::-first-letter`, when we know it won't affect us. + /// + /// TODO(emilio, bz): actually implement the logic for it. + fn may_generate_pseudo(&self, pseudo: &PseudoElement, _primary_style: &ComputedValues) -> bool { + // ::before/::after are always supported for now, though we could try to + // optimize out leaf elements. + + // ::first-letter and ::first-line are only supported for block-inside + // things, and only in Gecko, not Servo. Unfortunately, Gecko has + // block-inside things that might have any computed display value due to + // things like fieldsets, legends, etc. Need to figure out how this + // should work. + debug_assert!( + pseudo.is_eager(), + "Someone called may_generate_pseudo with a non-eager pseudo." + ); + true + } + + /// Returns true if this element may have a descendant needing style processing. + /// + /// Note that we cannot guarantee the existence of such an element, because + /// it may have been removed from the DOM between marking it for restyle and + /// the actual restyle traversal. + fn has_dirty_descendants(&self) -> bool; + + /// Returns whether state or attributes that may change style have changed + /// on the element, and thus whether the element has been snapshotted to do + /// restyle hint computation. + fn has_snapshot(&self) -> bool; + + /// Returns whether the current snapshot if present has been handled. + fn handled_snapshot(&self) -> bool; + + /// Flags this element as having handled already its snapshot. + unsafe fn set_handled_snapshot(&self); + + /// Returns whether the element's styles are up-to-date after traversal + /// (i.e. in post traversal). + fn has_current_styles(&self, data: &ElementData) -> bool { + if self.has_snapshot() && !self.handled_snapshot() { + return false; + } + + data.has_styles() && + // TODO(hiro): When an animating element moved into subtree of + // contenteditable element, there remains animation restyle hints in + // post traversal. It's generally harmless since the hints will be + // processed in a next styling but ideally it should be processed soon. + // + // Without this, we get failures in: + // layout/style/crashtests/1383319.html + // layout/style/crashtests/1383001.html + // + // https://bugzilla.mozilla.org/show_bug.cgi?id=1389675 tracks fixing + // this. + !data.hint.has_non_animation_invalidations() + } + + /// Flag that this element has a descendant for style processing. + /// + /// Only safe to call with exclusive access to the element. + unsafe fn set_dirty_descendants(&self); + + /// Flag that this element has no descendant for style processing. + /// + /// Only safe to call with exclusive access to the element. + unsafe fn unset_dirty_descendants(&self); + + /// Similar to the dirty_descendants but for representing a descendant of + /// the element needs to be updated in animation-only traversal. + fn has_animation_only_dirty_descendants(&self) -> bool { + false + } + + /// Flag that this element has a descendant for animation-only restyle + /// processing. + /// + /// Only safe to call with exclusive access to the element. + unsafe fn set_animation_only_dirty_descendants(&self) {} + + /// Flag that this element has no descendant for animation-only restyle processing. + /// + /// Only safe to call with exclusive access to the element. + unsafe fn unset_animation_only_dirty_descendants(&self) {} + + /// Clear all bits related describing the dirtiness of descendants. + /// + /// In Gecko, this corresponds to the regular dirty descendants bit, the + /// animation-only dirty descendants bit, and the lazy frame construction + /// descendants bit. + unsafe fn clear_descendant_bits(&self) { + self.unset_dirty_descendants(); + } + + /// Returns true if this element is a visited link. + /// + /// Servo doesn't support visited styles yet. + fn is_visited_link(&self) -> bool { + false + } + + /// Returns the pseudo-element implemented by this element, if any. + /// + /// Gecko traverses pseudo-elements during the style traversal, and we need + /// to know this so we can properly grab the pseudo-element style from the + /// parent element. + /// + /// Note that we still need to compute the pseudo-elements before-hand, + /// given otherwise we don't know if we need to create an element or not. + /// + /// Servo doesn't have to deal with this. + fn implemented_pseudo_element(&self) -> Option<PseudoElement> { + None + } + + /// Atomically stores the number of children of this node that we will + /// need to process during bottom-up traversal. + fn store_children_to_process(&self, n: isize); + + /// Atomically notes that a child has been processed during bottom-up + /// traversal. Returns the number of children left to process. + fn did_process_child(&self) -> isize; + + /// Gets a reference to the ElementData container, or creates one. + /// + /// Unsafe because it can race to allocate and leak if not used with + /// exclusive access to the element. + unsafe fn ensure_data(&self) -> AtomicRefMut<ElementData>; + + /// Clears the element data reference, if any. + /// + /// Unsafe following the same reasoning as ensure_data. + unsafe fn clear_data(&self); + + /// Whether there is an ElementData container. + fn has_data(&self) -> bool; + + /// Immutably borrows the ElementData. + fn borrow_data(&self) -> Option<AtomicRef<ElementData>>; + + /// Mutably borrows the ElementData. + fn mutate_data(&self) -> Option<AtomicRefMut<ElementData>>; + + /// Whether we should skip any root- or item-based display property + /// blockification on this element. (This function exists so that Gecko + /// native anonymous content can opt out of this style fixup.) + fn skip_item_display_fixup(&self) -> bool; + + /// In Gecko, element has a flag that represents the element may have + /// any type of animations or not to bail out animation stuff early. + /// Whereas Servo doesn't have such flag. + fn may_have_animations(&self) -> bool; + + /// Creates a task to update various animation state on a given (pseudo-)element. + #[cfg(feature = "gecko")] + fn update_animations( + &self, + before_change_style: Option<Arc<ComputedValues>>, + tasks: UpdateAnimationsTasks, + ); + + /// Creates a task to process post animation on a given element. + #[cfg(feature = "gecko")] + fn process_post_animation(&self, tasks: PostAnimationTasks); + + /// Returns true if the element has relevant animations. Relevant + /// animations are those animations that are affecting the element's style + /// or are scheduled to do so in the future. + fn has_animations(&self, context: &SharedStyleContext) -> bool; + + /// Returns true if the element has a CSS animation. The `context` and `pseudo_element` + /// arguments are only used by Servo, since it stores animations globally and pseudo-elements + /// are not in the DOM. + fn has_css_animations( + &self, + context: &SharedStyleContext, + pseudo_element: Option<PseudoElement>, + ) -> bool; + + /// Returns true if the element has a CSS transition (including running transitions and + /// completed transitions). The `context` and `pseudo_element` arguments are only used + /// by Servo, since it stores animations globally and pseudo-elements are not in the DOM. + fn has_css_transitions( + &self, + context: &SharedStyleContext, + pseudo_element: Option<PseudoElement>, + ) -> bool; + + /// Returns true if the element has animation restyle hints. + fn has_animation_restyle_hints(&self) -> bool { + let data = match self.borrow_data() { + Some(d) => d, + None => return false, + }; + return data.hint.has_animation_hint(); + } + + /// The shadow root this element is a host of. + fn shadow_root(&self) -> Option<<Self::ConcreteNode as TNode>::ConcreteShadowRoot>; + + /// The shadow root which roots the subtree this element is contained in. + fn containing_shadow(&self) -> Option<<Self::ConcreteNode as TNode>::ConcreteShadowRoot>; + + /// Return the element which we can use to look up rules in the selector + /// maps. + /// + /// This is always the element itself, except in the case where we are an + /// element-backed pseudo-element, in which case we return the originating + /// element. + fn rule_hash_target(&self) -> Self { + if self.is_pseudo_element() { + self.pseudo_element_originating_element() + .expect("Trying to collect rules for a detached pseudo-element") + } else { + *self + } + } + + /// Executes the callback for each applicable style rule data which isn't + /// the main document's data (which stores UA / author rules). + /// + /// The element passed to the callback is the containing shadow host for the + /// data if it comes from Shadow DOM. + /// + /// Returns whether normal document author rules should apply. + /// + /// TODO(emilio): We could separate the invalidation data for elements + /// matching in other scopes to avoid over-invalidation. + fn each_applicable_non_document_style_rule_data<'a, F>(&self, mut f: F) -> bool + where + Self: 'a, + F: FnMut(&'a CascadeData, Self), + { + use crate::rule_collector::containing_shadow_ignoring_svg_use; + + let target = self.rule_hash_target(); + let matches_user_and_content_rules = target.matches_user_and_content_rules(); + let mut doc_rules_apply = matches_user_and_content_rules; + + // Use the same rules to look for the containing host as we do for rule + // collection. + if let Some(shadow) = containing_shadow_ignoring_svg_use(target) { + doc_rules_apply = false; + if let Some(data) = shadow.style_data() { + f(data, shadow.host()); + } + } + + if let Some(shadow) = target.shadow_root() { + if let Some(data) = shadow.style_data() { + f(data, shadow.host()); + } + } + + let mut current = target.assigned_slot(); + while let Some(slot) = current { + // Slots can only have assigned nodes when in a shadow tree. + let shadow = slot.containing_shadow().unwrap(); + if let Some(data) = shadow.style_data() { + if data.any_slotted_rule() { + f(data, shadow.host()); + } + } + current = slot.assigned_slot(); + } + + if target.has_part_attr() { + if let Some(mut inner_shadow) = target.containing_shadow() { + loop { + let inner_shadow_host = inner_shadow.host(); + match inner_shadow_host.containing_shadow() { + Some(shadow) => { + if let Some(data) = shadow.style_data() { + if data.any_part_rule() { + f(data, shadow.host()) + } + } + // TODO: Could be more granular. + if !inner_shadow_host.exports_any_part() { + break; + } + inner_shadow = shadow; + }, + None => { + // TODO(emilio): Should probably distinguish with + // MatchesDocumentRules::{No,Yes,IfPart} or something so that we could + // skip some work. + doc_rules_apply = matches_user_and_content_rules; + break; + }, + } + } + } + } + + doc_rules_apply + } + + /// Returns true if one of the transitions needs to be updated on this element. We check all + /// the transition properties to make sure that updating transitions is necessary. + /// This method should only be called if might_needs_transitions_update returns true when + /// passed the same parameters. + #[cfg(feature = "gecko")] + fn needs_transitions_update( + &self, + before_change_style: &ComputedValues, + after_change_style: &ComputedValues, + ) -> bool; + + /// Returns the value of the `xml:lang=""` attribute (or, if appropriate, + /// the `lang=""` attribute) on this element. + fn lang_attr(&self) -> Option<AttrValue>; + + /// Returns whether this element's language matches the language tag + /// `value`. If `override_lang` is not `None`, it specifies the value + /// of the `xml:lang=""` or `lang=""` attribute to use in place of + /// looking at the element and its ancestors. (This argument is used + /// to implement matching of `:lang()` against snapshots.) + fn match_element_lang(&self, override_lang: Option<Option<AttrValue>>, value: &Lang) -> bool; + + /// Returns whether this element is the main body element of the HTML + /// document it is on. + fn is_html_document_body_element(&self) -> bool; + + /// Generate the proper applicable declarations due to presentational hints, + /// and insert them into `hints`. + fn synthesize_presentational_hints_for_legacy_attributes<V>( + &self, + visited_handling: VisitedHandlingMode, + hints: &mut V, + ) where + V: Push<ApplicableDeclarationBlock>; + + /// Returns element's local name. + fn local_name(&self) -> &<SelectorImpl as selectors::parser::SelectorImpl>::BorrowedLocalName; + + /// Returns element's namespace. + fn namespace(&self) + -> &<SelectorImpl as selectors::parser::SelectorImpl>::BorrowedNamespaceUrl; + + /// Returns the size of the element to be used in container size queries. + /// This will usually be the size of the content area of the primary box, + /// but can be None if there is no box or if some axis lacks size containment. + fn query_container_size( + &self, + display: &Display, + ) -> euclid::default::Size2D<Option<app_units::Au>>; + + /// Returns true if this element anchors a relative selector, now or after + /// a DOM mutation. + fn anchors_relative_selector(&self) -> bool; +} + +/// TNode and TElement aren't Send because we want to be careful and explicit +/// about our parallel traversal. However, there are certain situations +/// (including but not limited to the traversal) where we need to send DOM +/// objects to other threads. +/// +/// That's the reason why `SendNode` exists. +#[derive(Clone, Debug, PartialEq)] +pub struct SendNode<N: TNode>(N); +unsafe impl<N: TNode> Send for SendNode<N> {} +impl<N: TNode> SendNode<N> { + /// Unsafely construct a SendNode. + pub unsafe fn new(node: N) -> Self { + SendNode(node) + } +} +impl<N: TNode> Deref for SendNode<N> { + type Target = N; + fn deref(&self) -> &N { + &self.0 + } +} + +/// Same reason as for the existence of SendNode, SendElement does the proper +/// things for a given `TElement`. +#[derive(Debug, Eq, Hash, PartialEq)] +pub struct SendElement<E: TElement>(E); +unsafe impl<E: TElement> Send for SendElement<E> {} +impl<E: TElement> SendElement<E> { + /// Unsafely construct a SendElement. + pub unsafe fn new(el: E) -> Self { + SendElement(el) + } +} +impl<E: TElement> Deref for SendElement<E> { + type Target = E; + fn deref(&self) -> &E { + &self.0 + } +} |