selectors/
tree.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5//! Traits that nodes must implement. Breaks the otherwise-cyclic dependency
6//! between layout and style.
7
8use crate::attr::{AttrSelectorOperation, CaseSensitivity, NamespaceConstraint};
9use crate::bloom::BloomFilter;
10use crate::matching::{ElementSelectorFlags, MatchingContext};
11use crate::parser::SelectorImpl;
12use std::fmt::Debug;
13use std::ptr::NonNull;
14
15/// Opaque representation of an Element, for identity comparisons.
16#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
17pub struct OpaqueElement(NonNull<()>);
18
19unsafe impl Send for OpaqueElement {}
20// This should be safe given that we do not provide a way to recover
21// the original reference.
22unsafe impl Sync for OpaqueElement {}
23
24impl OpaqueElement {
25    /// Creates a new OpaqueElement from an arbitrarily-typed pointer.
26    pub fn new<T>(ptr: &T) -> Self {
27        unsafe {
28            OpaqueElement(NonNull::new_unchecked(
29                ptr as *const T as *const () as *mut (),
30            ))
31        }
32    }
33
34    /// Creates a new OpaqueElement from a type-erased non-null pointer
35    pub fn from_non_null_ptr(ptr: NonNull<()>) -> Self {
36        Self(ptr)
37    }
38
39    /// Returns a const ptr to the contained reference. Unsafe especially
40    /// since Element can be recovered and potentially-mutated.
41    pub unsafe fn as_const_ptr<T>(&self) -> *const T {
42        self.0.as_ptr() as *const T
43    }
44}
45
46pub trait Element: Sized + Clone + Debug {
47    type Impl: SelectorImpl;
48
49    /// Converts self into an opaque representation.
50    fn opaque(&self) -> OpaqueElement;
51
52    fn parent_element(&self) -> Option<Self>;
53
54    /// Whether the parent node of this element is a shadow root.
55    fn parent_node_is_shadow_root(&self) -> bool;
56
57    /// The host of the containing shadow root, if any.
58    fn containing_shadow_host(&self) -> Option<Self>;
59
60    /// The parent of a given pseudo-element, after matching a pseudo-element
61    /// selector.
62    ///
63    /// This is guaranteed to be called in a pseudo-element.
64    fn pseudo_element_originating_element(&self) -> Option<Self> {
65        debug_assert!(self.is_pseudo_element());
66        self.parent_element()
67    }
68
69    /// Whether we're matching on a pseudo-element.
70    fn is_pseudo_element(&self) -> bool;
71
72    /// Skips non-element nodes
73    fn prev_sibling_element(&self) -> Option<Self>;
74
75    /// Skips non-element nodes
76    fn next_sibling_element(&self) -> Option<Self>;
77
78    /// Skips non-element nodes
79    fn first_element_child(&self) -> Option<Self>;
80
81    fn is_html_element_in_html_document(&self) -> bool;
82
83    fn has_local_name(&self, local_name: &<Self::Impl as SelectorImpl>::BorrowedLocalName) -> bool;
84
85    /// Empty string for no namespace
86    fn has_namespace(&self, ns: &<Self::Impl as SelectorImpl>::BorrowedNamespaceUrl) -> bool;
87
88    /// Whether this element and the `other` element have the same local name and namespace.
89    fn is_same_type(&self, other: &Self) -> bool;
90
91    fn attr_matches(
92        &self,
93        ns: &NamespaceConstraint<&<Self::Impl as SelectorImpl>::NamespaceUrl>,
94        local_name: &<Self::Impl as SelectorImpl>::LocalName,
95        operation: &AttrSelectorOperation<&<Self::Impl as SelectorImpl>::AttrValue>,
96    ) -> bool;
97
98    fn has_attr_in_no_namespace(
99        &self,
100        local_name: &<Self::Impl as SelectorImpl>::LocalName,
101    ) -> bool {
102        self.attr_matches(
103            &NamespaceConstraint::Specific(&crate::parser::namespace_empty_string::<Self::Impl>()),
104            local_name,
105            &AttrSelectorOperation::Exists,
106        )
107    }
108
109    fn match_non_ts_pseudo_class(
110        &self,
111        pc: &<Self::Impl as SelectorImpl>::NonTSPseudoClass,
112        context: &mut MatchingContext<Self::Impl>,
113    ) -> bool;
114
115    fn match_pseudo_element(
116        &self,
117        pe: &<Self::Impl as SelectorImpl>::PseudoElement,
118        context: &mut MatchingContext<Self::Impl>,
119    ) -> bool;
120
121    /// Sets selector flags on the elemnt itself or the parent, depending on the
122    /// flags, which indicate what kind of work may need to be performed when
123    /// DOM state changes.
124    fn apply_selector_flags(&self, flags: ElementSelectorFlags);
125
126    /// Whether this element is a `link`.
127    fn is_link(&self) -> bool;
128
129    /// Returns whether the element is an HTML <slot> element.
130    fn is_html_slot_element(&self) -> bool;
131
132    /// Returns the assigned <slot> element this element is assigned to.
133    ///
134    /// Necessary for the `::slotted` pseudo-class.
135    fn assigned_slot(&self) -> Option<Self> {
136        None
137    }
138
139    fn has_id(
140        &self,
141        id: &<Self::Impl as SelectorImpl>::Identifier,
142        case_sensitivity: CaseSensitivity,
143    ) -> bool;
144
145    fn has_class(
146        &self,
147        name: &<Self::Impl as SelectorImpl>::Identifier,
148        case_sensitivity: CaseSensitivity,
149    ) -> bool;
150
151    fn has_custom_state(&self, name: &<Self::Impl as SelectorImpl>::Identifier) -> bool;
152
153    /// Returns the mapping from the `exportparts` attribute in the reverse
154    /// direction, that is, in an outer-tree -> inner-tree direction.
155    fn imported_part(
156        &self,
157        name: &<Self::Impl as SelectorImpl>::Identifier,
158    ) -> Option<<Self::Impl as SelectorImpl>::Identifier>;
159
160    fn is_part(&self, name: &<Self::Impl as SelectorImpl>::Identifier) -> bool;
161
162    /// Returns whether this element matches `:empty`.
163    ///
164    /// That is, whether it does not contain any child element or any non-zero-length text node.
165    /// See http://dev.w3.org/csswg/selectors-3/#empty-pseudo
166    fn is_empty(&self) -> bool;
167
168    /// Returns whether this element matches `:root`,
169    /// i.e. whether it is the root element of a document.
170    ///
171    /// Note: this can be false even if `.parent_element()` is `None`
172    /// if the parent node is a `DocumentFragment`.
173    fn is_root(&self) -> bool;
174
175    /// Returns whether this element should ignore matching nth child
176    /// selector.
177    fn ignores_nth_child_selectors(&self) -> bool {
178        false
179    }
180
181    /// Add hashes unique to this element to the given filter, returning true
182    /// if any got added.
183    fn add_element_unique_hashes(&self, filter: &mut BloomFilter) -> bool;
184}
selectors/tree.rs

selectors/
tree.rs
