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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
//! Gecko's definition of a pseudo-element.
//!
//! Note that a few autogenerated bits of this live in
//! `pseudo_element_definition.mako.rs`. If you touch that file, you probably
//! need to update the checked-in files for Servo.
use crate::gecko_bindings::structs::{self, PseudoStyleType};
use crate::properties::longhands::display::computed_value::T as Display;
use crate::properties::{ComputedValues, PropertyFlags};
use crate::selector_parser::{PseudoElementCascadeType, SelectorImpl};
use crate::str::{starts_with_ignore_ascii_case, string_as_ascii_lowercase};
use crate::string_cache::Atom;
use crate::values::serialize_atom_identifier;
use crate::values::AtomIdent;
use cssparser::{ToCss, Parser};
use static_prefs::pref;
use std::fmt;
use style_traits::ParseError;
include!(concat!(
env!("OUT_DIR"),
"/gecko/pseudo_element_definition.rs"
));
/// The target we are using for parsing pseudo-elements.
pub enum Target {
/// When parsing a selector, we want to use the full syntax.
Selector,
/// When parsing the pseudo-element string (from CSSOM), we only accept CusomIdent for named
/// view transition pseudo-elements.
Cssom,
}
/// The type to hold the value of `<pt-name-and-class-selector>`.
///
/// `<pt-name-and-class-selector> = <pt-name-selector> <pt-class-selector>? | <pt-class-selector>`
/// `<pt-name-selector> = '*' | <custom-ident>`
/// `<pt-class-selector> = ['.' <custom-ident>]+`
///
/// This type should have at least one element.
/// If there is no <pt-name-selector>, the first element would be the universal symbol, i.e. '*'.
/// In other words, when we match it, ".abc" is the same as "*.abc".
/// Note that we also serialize ".abc" as "*.abc".
///
/// We use a single ThinVec<> to represent this structure to avoid allocating too much memory for a
/// single selectors::parser::Component (max: 24 bytes) and PseudoElement (max: 16 bytes).
///
#[derive(Clone, Debug, Eq, Hash, MallocSizeOf, PartialEq, ToShmem)]
pub struct PtNameAndClassSelector(thin_vec::ThinVec<Atom>);
impl PtNameAndClassSelector {
/// Constructs a new one from a name.
pub fn from_name(name: Atom) -> Self {
Self(thin_vec![name])
}
/// Returns the name component.
pub fn name(&self) -> &Atom {
debug_assert!(!self.0.is_empty());
self.0.first().expect("Shouldn't be empty")
}
/// Returns the classes component.
pub fn classes(&self) -> &[Atom] {
debug_assert!(!self.0.is_empty());
&self.0[1..]
}
/// Returns the vector we store.
pub fn name_and_classes(&self) -> &thin_vec::ThinVec<Atom> {
&self.0
}
/// Parse the pseudo-element tree name and/or class.
/// |for_selector| is true if we are parsing the CSS selectors and so need to check the
/// universal symbol, i.e. '*', and classes.
// Note: We share the same type for both pseudo-element and pseudo-element selector. The
// universal symbol (i.e. '*') and `<pt-class-selector>` are used only in the selector (for
// matching).
pub fn parse<'i, 't>(
input: &mut Parser<'i, 't>,
target: Target,
) -> Result<Self, ParseError<'i>> {
use crate::values::CustomIdent;
use cssparser::Token;
use style_traits::StyleParseErrorKind;
// <pt-name-selector> = '*' | <custom-ident>
let parse_pt_name = |input: &mut Parser<'i, '_>| {
// For pseudo-element string, we don't accept '*'.
if matches!(target, Target::Selector) &&
input.try_parse(|i| i.expect_delim('*')).is_ok()
{
Ok(atom!("*"))
} else {
CustomIdent::parse(input, &[]).map(|c| c.0)
}
};
let name = input.try_parse(parse_pt_name);
// Skip <pt-class-selector> for pseudo-element string.
if matches!(target, Target::Cssom) {
return name.map(Self::from_name);
}
// <pt-class-selector> = ['.' <custom-ident>]+
let parse_pt_class = |input: &mut Parser<'i, '_>| {
// The white space is forbidden:
// 1. Between <pt-name-selector> and <pt-class-selector>
// 2. Between any of the components of <pt-class-selector>.
let location = input.current_source_location();
match input.next_including_whitespace()? {
Token::Delim('.') => (),
t => return Err(location.new_unexpected_token_error(t.clone())),
}
// Whitespace is not allowed between '.' and the class name.
if let Ok(token) = input.try_parse(|i| i.expect_whitespace()) {
return Err(input.new_unexpected_token_error(Token::WhiteSpace(token)));
}
CustomIdent::parse(input, &[]).map(|c| c.0)
};
// If there is no `<pt-name-selector>`, it's fine to have whitespaces before the first '.'.
if name.is_err() {
input.skip_whitespace();
}
let mut classes = thin_vec::ThinVec::new();
while let Ok(class) = input.try_parse(parse_pt_class) {
classes.push(class);
}
// If we don't have `<pt-name-selector>`, we must have `<pt-class-selector>`, per the
// syntax: `<pt-name-selector> <pt-class-selector>? | <pt-class-selector>`.
if name.is_err() && classes.is_empty() {
return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
}
// Use the universal symbol as the first element to present the part of
// `<pt-name-selector>` because they are equivalent (and the serialization is the same).
let mut result = thin_vec![name.unwrap_or(atom!("*"))];
result.append(&mut classes);
Ok(Self(result))
}
}
impl ToCss for PtNameAndClassSelector {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result
where
W: fmt::Write,
{
let name = self.name();
if name == &atom!("*") {
// serialize_atom_identifier() may serialize "*" as "\*", so we handle it separately.
dest.write_char('*')?;
} else {
serialize_atom_identifier(name, dest)?;
}
for class in self.classes() {
dest.write_char('.')?;
serialize_atom_identifier(class, dest)?;
}
Ok(())
}
}
impl ::selectors::parser::PseudoElement for PseudoElement {
type Impl = SelectorImpl;
// ::slotted() should support all tree-abiding pseudo-elements, see
#[inline]
fn valid_after_slotted(&self) -> bool {
matches!(
*self,
Self::Before |
Self::After |
Self::Marker |
Self::Placeholder |
Self::FileSelectorButton |
Self::DetailsContent
)
}
#[inline]
fn accepts_state_pseudo_classes(&self) -> bool {
// Note: if the pseudo element is a descendants of a pseudo element, `only-child` should be
// allowed after it.
self.supports_user_action_state() || self.is_in_pseudo_element_tree()
}
#[inline]
fn specificity_count(&self) -> u32 {
self.specificity_count()
}
#[inline]
fn is_in_pseudo_element_tree(&self) -> bool {
// All the named view transition pseudo-elements are the descendants of a pseudo-element
// root.
self.is_named_view_transition()
}
/// Whether this pseudo-element is "element-backed", which means that it inherits from its regular
/// flat tree parent, which might not be the originating element.
#[inline]
fn is_element_backed(&self) -> bool {
// Note: We doen't include ::view-transition here because it inherits from the originating
// element, instead of the snapshot containing block.
self.is_named_view_transition() || *self == PseudoElement::DetailsContent
}
}
impl PseudoElement {
/// Returns the kind of cascade type that a given pseudo is going to use.
///
/// In Gecko we only compute ::before and ::after eagerly. We save the rules
/// for anonymous boxes separately, so we resolve them as precomputed
/// pseudos.
///
/// We resolve the others lazily, see `Servo_ResolvePseudoStyle`.
pub fn cascade_type(&self) -> PseudoElementCascadeType {
if self.is_eager() {
debug_assert!(!self.is_anon_box());
return PseudoElementCascadeType::Eager;
}
if self.is_precomputed() {
return PseudoElementCascadeType::Precomputed;
}
PseudoElementCascadeType::Lazy
}
/// Gets the canonical index of this eagerly-cascaded pseudo-element.
#[inline]
pub fn eager_index(&self) -> usize {
EAGER_PSEUDOS
.iter()
.position(|p| p == self)
.expect("Not an eager pseudo")
}
/// Creates a pseudo-element from an eager index.
#[inline]
pub fn from_eager_index(i: usize) -> Self {
EAGER_PSEUDOS[i].clone()
}
/// Whether animations for the current pseudo element are stored in the
/// parent element.
#[inline]
pub fn animations_stored_in_parent(&self) -> bool {
matches!(*self, Self::Before | Self::After | Self::Marker)
}
/// Whether the current pseudo element is ::before or ::after.
#[inline]
pub fn is_before_or_after(&self) -> bool {
matches!(*self, Self::Before | Self::After)
}
/// Whether this pseudo-element is the ::before pseudo.
#[inline]
pub fn is_before(&self) -> bool {
*self == PseudoElement::Before
}
/// Whether this pseudo-element is the ::after pseudo.
#[inline]
pub fn is_after(&self) -> bool {
*self == PseudoElement::After
}
/// Whether this pseudo-element is the ::marker pseudo.
#[inline]
pub fn is_marker(&self) -> bool {
*self == PseudoElement::Marker
}
/// Whether this pseudo-element is the ::selection pseudo.
#[inline]
pub fn is_selection(&self) -> bool {
*self == PseudoElement::Selection
}
/// Whether this pseudo-element is ::first-letter.
#[inline]
pub fn is_first_letter(&self) -> bool {
*self == PseudoElement::FirstLetter
}
/// Whether this pseudo-element is ::first-line.
#[inline]
pub fn is_first_line(&self) -> bool {
*self == PseudoElement::FirstLine
}
/// Whether this pseudo-element is the ::-moz-color-swatch pseudo.
#[inline]
pub fn is_color_swatch(&self) -> bool {
*self == PseudoElement::MozColorSwatch
}
/// Whether this pseudo-element is lazily-cascaded.
#[inline]
pub fn is_lazy(&self) -> bool {
!self.is_eager() && !self.is_precomputed()
}
/// The identifier of the highlight this pseudo-element represents.
pub fn highlight_name(&self) -> Option<&AtomIdent> {
match *self {
Self::Highlight(ref name) => Some(name),
_ => None,
}
}
/// Whether this pseudo-element is the ::highlight pseudo.
pub fn is_highlight(&self) -> bool {
matches!(*self, Self::Highlight(_))
}
/// Whether this pseudo-element is the ::target-text pseudo.
#[inline]
pub fn is_target_text(&self) -> bool {
*self == PseudoElement::TargetText
}
/// Whether this pseudo-element is a named view transition pseudo-element.
pub fn is_named_view_transition(&self) -> bool {
matches!(
*self,
Self::ViewTransitionGroup(..) |
Self::ViewTransitionImagePair(..) |
Self::ViewTransitionOld(..) |
Self::ViewTransitionNew(..)
)
}
/// The count we contribute to the specificity from this pseudo-element.
pub fn specificity_count(&self) -> u32 {
match *self {
Self::ViewTransitionGroup(ref name_and_class) |
Self::ViewTransitionImagePair(ref name_and_class) |
Self::ViewTransitionOld(ref name_and_class) |
Self::ViewTransitionNew(ref name_and_class) => {
// The specificity of a named view transition pseudo-element selector with either:
// 1. a <pt-name-selector> with a <custom-ident>; or
// 2. a <pt-class-selector> with at least one <custom-ident>,
// is equivalent to a type selector.
//
// The specificity of a named view transition pseudo-element selector with a `*`
// argument and with an empty <pt-class-selector> is zero.
(name_and_class.name() != &atom!("*") || !name_and_class.classes().is_empty())
as u32
},
_ => 1,
}
}
/// Whether this pseudo-element supports user action selectors.
pub fn supports_user_action_state(&self) -> bool {
(self.flags() & structs::CSS_PSEUDO_ELEMENT_SUPPORTS_USER_ACTION_STATE) != 0
}
/// Whether this pseudo-element is enabled for all content.
pub fn enabled_in_content(&self) -> bool {
match *self {
Self::Highlight(..) => pref!("dom.customHighlightAPI.enabled"),
Self::TargetText => pref!("dom.text_fragments.enabled"),
Self::SliderFill | Self::SliderTrack | Self::SliderThumb => {
pref!("layout.css.modern-range-pseudos.enabled")
},
Self::DetailsContent => {
pref!("layout.css.details-content.enabled")
},
Self::ViewTransition |
Self::ViewTransitionGroup(..) |
Self::ViewTransitionImagePair(..) |
Self::ViewTransitionOld(..) |
Self::ViewTransitionNew(..) => pref!("dom.viewTransitions.enabled"),
// If it's not explicitly enabled in UA sheets or chrome, then we're enabled for
// content.
_ => (self.flags() & structs::CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS_AND_CHROME) == 0,
}
}
/// Whether this pseudo is enabled explicitly in UA sheets.
pub fn enabled_in_ua_sheets(&self) -> bool {
(self.flags() & structs::CSS_PSEUDO_ELEMENT_ENABLED_IN_UA_SHEETS) != 0
}
/// Whether this pseudo is enabled explicitly in chrome sheets.
pub fn enabled_in_chrome(&self) -> bool {
(self.flags() & structs::CSS_PSEUDO_ELEMENT_ENABLED_IN_CHROME) != 0
}
/// Whether this pseudo-element skips flex/grid container display-based
/// fixup.
#[inline]
pub fn skip_item_display_fixup(&self) -> bool {
(self.flags() & structs::CSS_PSEUDO_ELEMENT_IS_FLEX_OR_GRID_ITEM) == 0
}
/// Whether this pseudo-element is precomputed.
#[inline]
pub fn is_precomputed(&self) -> bool {
self.is_anon_box() && !self.is_tree_pseudo_element()
}
/// Property flag that properties must have to apply to this pseudo-element.
#[inline]
pub fn property_restriction(&self) -> Option<PropertyFlags> {
Some(match *self {
PseudoElement::FirstLetter => PropertyFlags::APPLIES_TO_FIRST_LETTER,
PseudoElement::FirstLine => PropertyFlags::APPLIES_TO_FIRST_LINE,
PseudoElement::Placeholder => PropertyFlags::APPLIES_TO_PLACEHOLDER,
PseudoElement::Cue => PropertyFlags::APPLIES_TO_CUE,
PseudoElement::Marker if static_prefs::pref!("layout.css.marker.restricted") => {
PropertyFlags::APPLIES_TO_MARKER
},
_ => return None,
})
}
/// Whether this pseudo-element should actually exist if it has
/// the given styles.
pub fn should_exist(&self, style: &ComputedValues) -> bool {
debug_assert!(self.is_eager());
if style.get_box().clone_display() == Display::None {
return false;
}
if self.is_before_or_after() && style.ineffective_content_property() {
return false;
}
true
}
/// Parse the pseudo-element string without the check of enabled state. This may includes
/// all possible PseudoElement, including tree pseudo-elements and anonymous box.
pub fn parse_ignore_enabled_state<'i, 't>(
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
use crate::gecko::selector_parser;
use cssparser::Token;
use selectors::parser::{is_css2_pseudo_element, SelectorParseErrorKind};
use style_traits::StyleParseErrorKind;
// The pseudo-element string should start with ':'.
input.expect_colon()?;
let location = input.current_source_location();
let next = input.next_including_whitespace()?;
if !matches!(next, Token::Colon) {
// Parse a CSS2 pseudo-element.
let name = match next {
Token::Ident(name) if is_css2_pseudo_element(&name) => name,
_ => return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError)),
};
return PseudoElement::from_slice(&name, false).ok_or(location.new_custom_error(
SelectorParseErrorKind::UnsupportedPseudoClassOrElement(name.clone()),
))
}
// Now we have double colons, so check the following tokens.
match input.next_including_whitespace()?.clone() {
Token::Ident(name) => {
// We don't need to parse unknown ::-webkit-* pseudo-elements in this function.
PseudoElement::from_slice(&name, false).ok_or(input.new_custom_error(
SelectorParseErrorKind::UnsupportedPseudoClassOrElement(name),
))
},
Token::Function(name) => {
// Note: ::slotted() and ::part() are not accepted in getComputedStyle().
input.parse_nested_block(|input| {
selector_parser::parse_functional_pseudo_element_with_name(
name,
input,
Target::Cssom,
)
})
},
t => return Err(input.new_unexpected_token_error(t)),
}
}
/// Returns true if this pseudo-element matches its selector.
pub fn matches_named_view_transition_pseudo_element(
&self,
selector: &Self,
element: &super::wrapper::GeckoElement,
) -> bool {
use crate::gecko_bindings::bindings;
match (self, selector) {
(
&Self::ViewTransitionGroup(ref name),
&Self::ViewTransitionGroup(ref s_name_class),
) |
(
&Self::ViewTransitionImagePair(ref name),
&Self::ViewTransitionImagePair(ref s_name_class),
) |
(&Self::ViewTransitionOld(ref name), &Self::ViewTransitionOld(ref s_name_class)) |
(&Self::ViewTransitionNew(ref name), &Self::ViewTransitionNew(ref s_name_class)) => {
// Named view transition pseudos accept the universal selector as the name, so we
// check it first.
let s_name = s_name_class.name();
if s_name != name.name() && s_name != &atom!("*") {
return false;
}
// We have to check class list only when the name is matched and there are one or
// more <pt-class-selector>s.
s_name_class.classes().is_empty() ||
unsafe {
bindings::Gecko_MatchViewTransitionClass(
element.0,
s_name_class.name_and_classes(),
)
}
},
_ => false,
}
}
}