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-rw-r--r--servo/components/selectors/tree.rs152
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+/* 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/. */
+
+//! Traits that nodes must implement. Breaks the otherwise-cyclic dependency
+//! between layout and style.
+
+use crate::attr::{AttrSelectorOperation, CaseSensitivity, NamespaceConstraint};
+use crate::matching::{ElementSelectorFlags, MatchingContext};
+use crate::parser::SelectorImpl;
+use std::fmt::Debug;
+use std::ptr::NonNull;
+
+/// Opaque representation of an Element, for identity comparisons.
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+pub struct OpaqueElement(NonNull<()>);
+
+unsafe impl Send for OpaqueElement {}
+
+impl OpaqueElement {
+ /// Creates a new OpaqueElement from an arbitrarily-typed pointer.
+ pub fn new<T>(ptr: &T) -> Self {
+ unsafe {
+ OpaqueElement(NonNull::new_unchecked(
+ ptr as *const T as *const () as *mut (),
+ ))
+ }
+ }
+}
+
+pub trait Element: Sized + Clone + Debug {
+ type Impl: SelectorImpl;
+
+ /// Converts self into an opaque representation.
+ fn opaque(&self) -> OpaqueElement;
+
+ fn parent_element(&self) -> Option<Self>;
+
+ /// Whether the parent node of this element is a shadow root.
+ fn parent_node_is_shadow_root(&self) -> bool;
+
+ /// The host of the containing shadow root, if any.
+ fn containing_shadow_host(&self) -> Option<Self>;
+
+ /// The parent of a given pseudo-element, after matching a pseudo-element
+ /// selector.
+ ///
+ /// This is guaranteed to be called in a pseudo-element.
+ fn pseudo_element_originating_element(&self) -> Option<Self> {
+ debug_assert!(self.is_pseudo_element());
+ self.parent_element()
+ }
+
+ /// Whether we're matching on a pseudo-element.
+ fn is_pseudo_element(&self) -> bool;
+
+ /// Skips non-element nodes
+ fn prev_sibling_element(&self) -> Option<Self>;
+
+ /// Skips non-element nodes
+ fn next_sibling_element(&self) -> Option<Self>;
+
+ /// Skips non-element nodes
+ fn first_element_child(&self) -> Option<Self>;
+
+ fn is_html_element_in_html_document(&self) -> bool;
+
+ fn has_local_name(&self, local_name: &<Self::Impl as SelectorImpl>::BorrowedLocalName) -> bool;
+
+ /// Empty string for no namespace
+ fn has_namespace(&self, ns: &<Self::Impl as SelectorImpl>::BorrowedNamespaceUrl) -> bool;
+
+ /// Whether this element and the `other` element have the same local name and namespace.
+ fn is_same_type(&self, other: &Self) -> bool;
+
+ fn attr_matches(
+ &self,
+ ns: &NamespaceConstraint<&<Self::Impl as SelectorImpl>::NamespaceUrl>,
+ local_name: &<Self::Impl as SelectorImpl>::LocalName,
+ operation: &AttrSelectorOperation<&<Self::Impl as SelectorImpl>::AttrValue>,
+ ) -> bool;
+
+ fn match_non_ts_pseudo_class(
+ &self,
+ pc: &<Self::Impl as SelectorImpl>::NonTSPseudoClass,
+ context: &mut MatchingContext<Self::Impl>,
+ ) -> bool;
+
+ fn match_pseudo_element(
+ &self,
+ pe: &<Self::Impl as SelectorImpl>::PseudoElement,
+ context: &mut MatchingContext<Self::Impl>,
+ ) -> bool;
+
+ /// Sets selector flags on the elemnt itself or the parent, depending on the
+ /// flags, which indicate what kind of work may need to be performed when
+ /// DOM state changes.
+ fn apply_selector_flags(&self, flags: ElementSelectorFlags);
+
+ /// Whether this element is a `link`.
+ fn is_link(&self) -> bool;
+
+ /// Returns whether the element is an HTML <slot> element.
+ fn is_html_slot_element(&self) -> bool;
+
+ /// Returns the assigned <slot> element this element is assigned to.
+ ///
+ /// Necessary for the `::slotted` pseudo-class.
+ fn assigned_slot(&self) -> Option<Self> {
+ None
+ }
+
+ fn has_id(
+ &self,
+ id: &<Self::Impl as SelectorImpl>::Identifier,
+ case_sensitivity: CaseSensitivity,
+ ) -> bool;
+
+ fn has_class(
+ &self,
+ name: &<Self::Impl as SelectorImpl>::Identifier,
+ case_sensitivity: CaseSensitivity,
+ ) -> bool;
+
+ /// Returns the mapping from the `exportparts` attribute in the reverse
+ /// direction, that is, in an outer-tree -> inner-tree direction.
+ fn imported_part(
+ &self,
+ name: &<Self::Impl as SelectorImpl>::Identifier,
+ ) -> Option<<Self::Impl as SelectorImpl>::Identifier>;
+
+ fn is_part(&self, name: &<Self::Impl as SelectorImpl>::Identifier) -> bool;
+
+ /// Returns whether this element matches `:empty`.
+ ///
+ /// That is, whether it does not contain any child element or any non-zero-length text node.
+ /// See http://dev.w3.org/csswg/selectors-3/#empty-pseudo
+ fn is_empty(&self) -> bool;
+
+ /// Returns whether this element matches `:root`,
+ /// i.e. whether it is the root element of a document.
+ ///
+ /// Note: this can be false even if `.parent_element()` is `None`
+ /// if the parent node is a `DocumentFragment`.
+ fn is_root(&self) -> bool;
+
+ /// Returns whether this element should ignore matching nth child
+ /// selector.
+ fn ignores_nth_child_selectors(&self) -> bool {
+ false
+ }
+}