servo/components/style/gecko/selector_parser.rs

419 lines
18 KiB
Rust

/* 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 http://mozilla.org/MPL/2.0/. */
//! Gecko-specific bits for selector-parsing.
use cssparser::{BasicParseError, Parser, ToCss, Token, CowRcStr};
use element_state::ElementState;
use gecko_bindings::structs::CSSPseudoClassType;
use selector_parser::{SelectorParser, PseudoElementCascadeType};
use selectors::parser::{Selector, SelectorMethods, SelectorParseError};
use selectors::visitor::SelectorVisitor;
use std::fmt;
use string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
use style_traits::{ParseError, StyleParseError};
pub use gecko::pseudo_element::{PseudoElement, EAGER_PSEUDOS, EAGER_PSEUDO_COUNT};
pub use gecko::snapshot::SnapshotMap;
bitflags! {
flags NonTSPseudoClassFlag: u8 {
// See NonTSPseudoClass::is_internal()
const PSEUDO_CLASS_INTERNAL = 0x01,
}
}
/// The type used for storing pseudo-class string arguments.
pub type PseudoClassStringArg = Box<[u16]>;
macro_rules! pseudo_class_name {
(bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
#[doc = "Our representation of a non tree-structural pseudo-class."]
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum NonTSPseudoClass {
$(
#[doc = $css]
$name,
)*
$(
#[doc = $s_css]
$s_name(PseudoClassStringArg),
)*
$(
#[doc = $k_css]
$k_name(Box<[u16]>),
)*
/// The non-standard `:-moz-any` pseudo-class.
///
/// TODO(emilio): We disallow combinators and pseudos here, so we
/// should use SimpleSelector instead
MozAny(Box<[Selector<SelectorImpl>]>),
}
}
}
apply_non_ts_list!(pseudo_class_name);
impl ToCss for NonTSPseudoClass {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
use cssparser::CssStringWriter;
use fmt::Write;
macro_rules! pseudo_class_serialize {
(bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
match *self {
$(NonTSPseudoClass::$name => concat!(":", $css),)*
$(NonTSPseudoClass::$s_name(ref s) => {
write!(dest, ":{}(", $s_css)?;
{
// FIXME(emilio): Avoid the extra allocation!
let mut css = CssStringWriter::new(dest);
// Discount the null char in the end from the
// string.
css.write_str(&String::from_utf16(&s[..s.len() - 1]).unwrap())?;
}
return dest.write_str(")")
}, )*
$(NonTSPseudoClass::$k_name(ref s) => {
// Don't include the terminating nul.
let value = String::from_utf16(&s[..s.len() - 1]).unwrap();
return write!(dest, ":{}({})", $k_css, value)
}, )*
NonTSPseudoClass::MozAny(ref selectors) => {
dest.write_str(":-moz-any(")?;
let mut iter = selectors.iter();
let first = iter.next().expect(":-moz-any must have at least 1 selector");
first.to_css(dest)?;
for selector in iter {
dest.write_str(", ")?;
selector.to_css(dest)?;
}
return dest.write_str(")")
}
}
}
}
let ser = apply_non_ts_list!(pseudo_class_serialize);
dest.write_str(ser)
}
}
impl SelectorMethods for NonTSPseudoClass {
type Impl = SelectorImpl;
fn visit<V>(&self, visitor: &mut V) -> bool
where V: SelectorVisitor<Impl = Self::Impl>,
{
if let NonTSPseudoClass::MozAny(ref selectors) = *self {
for selector in selectors.iter() {
if !selector.visit(visitor) {
return false;
}
}
}
true
}
}
impl NonTSPseudoClass {
/// A pseudo-class is internal if it can only be used inside
/// user agent style sheets.
pub fn is_internal(&self) -> bool {
macro_rules! check_flag {
(_) => (false);
($flags:expr) => ($flags.contains(PSEUDO_CLASS_INTERNAL));
}
macro_rules! pseudo_class_check_internal {
(bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
match *self {
$(NonTSPseudoClass::$name => check_flag!($flags),)*
$(NonTSPseudoClass::$s_name(..) => check_flag!($s_flags),)*
$(NonTSPseudoClass::$k_name(..) => check_flag!($k_flags),)*
NonTSPseudoClass::MozAny(_) => false,
}
}
}
apply_non_ts_list!(pseudo_class_check_internal)
}
/// https://drafts.csswg.org/selectors-4/#useraction-pseudos
///
/// We intentionally skip the link-related ones.
pub fn is_safe_user_action_state(&self) -> bool {
matches!(*self, NonTSPseudoClass::Hover |
NonTSPseudoClass::Active |
NonTSPseudoClass::Focus)
}
/// Get the state flag associated with a pseudo-class, if any.
pub fn state_flag(&self) -> ElementState {
macro_rules! flag {
(_) => (ElementState::empty());
($state:ident) => (::element_state::$state);
}
macro_rules! pseudo_class_state {
(bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
match *self {
$(NonTSPseudoClass::$name => flag!($state),)*
$(NonTSPseudoClass::$s_name(..) => flag!($s_state),)*
$(NonTSPseudoClass::$k_name(..) => flag!($k_state),)*
NonTSPseudoClass::MozAny(..) => ElementState::empty(),
}
}
}
apply_non_ts_list!(pseudo_class_state)
}
/// Returns true if the given pseudoclass should trigger style sharing cache
/// revalidation.
pub fn needs_cache_revalidation(&self) -> bool {
self.state_flag().is_empty() &&
!matches!(*self,
// :-moz-any is handled by the revalidation visitor walking
// the things inside it; it does not need to cause
// revalidation on its own.
NonTSPseudoClass::MozAny(_) |
// :dir() depends on state only, but doesn't use state_flag
// because its semantics don't quite match. Nevertheless, it
// doesn't need cache revalidation, because we already compare
// states for elements and candidates.
NonTSPseudoClass::Dir(_) |
// :-moz-is-html only depends on the state of the document and
// the namespace of the element; the former is invariant
// across all the elements involved and the latter is already
// checked for by our caching precondtions.
NonTSPseudoClass::MozIsHTML |
// :-moz-placeholder is parsed but never matches.
NonTSPseudoClass::MozPlaceholder |
// :-moz-locale-dir and :-moz-window-inactive depend only on
// the state of the document, which is invariant across all
// the elements involved in a given style cache.
NonTSPseudoClass::MozLocaleDir(_) |
NonTSPseudoClass::MozWindowInactive |
// Similar for the document themes.
NonTSPseudoClass::MozLWTheme |
NonTSPseudoClass::MozLWThemeBrightText |
NonTSPseudoClass::MozLWThemeDarkText
)
}
/// Convert NonTSPseudoClass to Gecko's CSSPseudoClassType.
pub fn to_gecko_pseudoclasstype(&self) -> Option<CSSPseudoClassType> {
macro_rules! gecko_type {
(_) => (None);
($gecko_type:ident) =>
(Some(::gecko_bindings::structs::CSSPseudoClassType::$gecko_type));
}
macro_rules! pseudo_class_geckotype {
(bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
match *self {
$(NonTSPseudoClass::$name => gecko_type!($gecko_type),)*
$(NonTSPseudoClass::$s_name(..) => gecko_type!($s_gecko_type),)*
$(NonTSPseudoClass::$k_name(..) => gecko_type!($k_gecko_type),)*
NonTSPseudoClass::MozAny(_) => gecko_type!(any),
}
}
}
apply_non_ts_list!(pseudo_class_geckotype)
}
/// Returns true if the evaluation of the pseudo-class depends on the
/// element's attributes.
pub fn is_attr_based(&self) -> bool {
matches!(*self,
NonTSPseudoClass::MozTableBorderNonzero |
NonTSPseudoClass::MozBrowserFrame |
NonTSPseudoClass::Lang(..))
}
}
/// The dummy struct we use to implement our selector parsing.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct SelectorImpl;
impl ::selectors::SelectorImpl for SelectorImpl {
type AttrValue = Atom;
type Identifier = Atom;
type ClassName = Atom;
type LocalName = Atom;
type NamespacePrefix = Atom;
type NamespaceUrl = Namespace;
type BorrowedNamespaceUrl = WeakNamespace;
type BorrowedLocalName = WeakAtom;
type PseudoElement = PseudoElement;
type NonTSPseudoClass = NonTSPseudoClass;
#[inline]
fn is_active_or_hover(pseudo_class: &Self::NonTSPseudoClass) -> bool {
matches!(*pseudo_class, NonTSPseudoClass::Active |
NonTSPseudoClass::Hover)
}
}
impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
type Impl = SelectorImpl;
type Error = StyleParseError<'i>;
fn is_pseudo_element_allows_single_colon(name: &CowRcStr<'i>) -> bool {
::selectors::parser::is_css2_pseudo_element(name) ||
name.starts_with("-moz-tree-") // tree pseudo-elements
}
fn parse_non_ts_pseudo_class(&self, name: CowRcStr<'i>)
-> Result<NonTSPseudoClass, ParseError<'i>> {
macro_rules! pseudo_class_parse {
(bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
match_ignore_ascii_case! { &name,
$($css => NonTSPseudoClass::$name,)*
_ => return Err(::selectors::parser::SelectorParseError::UnexpectedIdent(
name.clone()).into())
}
}
}
let pseudo_class = apply_non_ts_list!(pseudo_class_parse);
if !pseudo_class.is_internal() || self.in_user_agent_stylesheet() {
Ok(pseudo_class)
} else {
Err(SelectorParseError::UnexpectedIdent(name).into())
}
}
fn parse_non_ts_functional_pseudo_class<'t>(&self,
name: CowRcStr<'i>,
parser: &mut Parser<'i, 't>)
-> Result<NonTSPseudoClass, ParseError<'i>> {
macro_rules! pseudo_class_string_parse {
(bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
string: [$(($s_css:expr, $s_name:ident, $s_gecko_type:tt, $s_state:tt, $s_flags:tt),)*],
keyword: [$(($k_css:expr, $k_name:ident, $k_gecko_type:tt, $k_state:tt, $k_flags:tt),)*]) => {
match_ignore_ascii_case! { &name,
$($s_css => {
let name = parser.expect_ident_or_string()?;
// convert to null terminated utf16 string
// since that's what Gecko deals with
let utf16: Vec<u16> = name.encode_utf16().chain(Some(0u16)).collect();
NonTSPseudoClass::$s_name(utf16.into_boxed_slice())
}, )*
$($k_css => {
let name = parser.expect_ident()?;
// Convert to ASCII-lowercase nul-terminated UTF-16 string.
let utf16: Vec<u16> = name.encode_utf16().map(utf16_to_ascii_lowercase)
.chain(Some(0u16)).collect();
NonTSPseudoClass::$k_name(utf16.into_boxed_slice())
}, )*
"-moz-any" => {
let selectors = parser.parse_comma_separated(|input| {
Selector::parse(self, input)
})?;
// Selectors inside `:-moz-any` may not include combinators.
if selectors.iter().flat_map(|x| x.iter_raw_match_order()).any(|s| s.is_combinator()) {
return Err(SelectorParseError::UnexpectedIdent("-moz-any".into()).into())
}
NonTSPseudoClass::MozAny(selectors.into_boxed_slice())
}
_ => return Err(SelectorParseError::UnexpectedIdent(name.clone()).into())
}
}
}
let pseudo_class = apply_non_ts_list!(pseudo_class_string_parse);
if !pseudo_class.is_internal() || self.in_user_agent_stylesheet() {
Ok(pseudo_class)
} else {
Err(SelectorParseError::UnexpectedIdent(name).into())
}
}
fn parse_pseudo_element(&self, name: CowRcStr<'i>) -> Result<PseudoElement, ParseError<'i>> {
PseudoElement::from_slice(&name, self.in_user_agent_stylesheet())
.ok_or(SelectorParseError::UnexpectedIdent(name.clone()).into())
}
fn parse_functional_pseudo_element<'t>(&self, name: CowRcStr<'i>,
parser: &mut Parser<'i, 't>)
-> Result<PseudoElement, ParseError<'i>> {
if name.starts_with("-moz-tree-") {
// Tree pseudo-elements can have zero or more arguments,
// separated by either comma or space.
let mut args = Vec::new();
loop {
match parser.next() {
Ok(&Token::Ident(ref ident)) => args.push(ident.as_ref().to_owned()),
Ok(&Token::Comma) => {},
Ok(t) => return Err(BasicParseError::UnexpectedToken(t.clone()).into()),
Err(BasicParseError::EndOfInput) => break,
_ => unreachable!("Parser::next() shouldn't return any other error"),
}
}
let args = args.into_boxed_slice();
if let Some(pseudo) = PseudoElement::tree_pseudo_element(&name, args) {
return Ok(pseudo);
}
}
Err(SelectorParseError::UnexpectedIdent(name.clone()).into())
}
fn default_namespace(&self) -> Option<Namespace> {
self.namespaces.default.clone().as_ref().map(|&(ref ns, _)| ns.clone())
}
fn namespace_for_prefix(&self, prefix: &Atom) -> Option<Namespace> {
self.namespaces.prefixes.get(prefix).map(|&(ref ns, _)| ns.clone())
}
}
impl SelectorImpl {
#[inline]
/// Legacy alias for PseudoElement::cascade_type.
pub fn pseudo_element_cascade_type(pseudo: &PseudoElement) -> PseudoElementCascadeType {
pseudo.cascade_type()
}
/// A helper to traverse each eagerly cascaded pseudo-element, executing
/// `fun` on it.
#[inline]
pub fn each_eagerly_cascaded_pseudo_element<F>(mut fun: F)
where F: FnMut(PseudoElement),
{
for pseudo in &EAGER_PSEUDOS {
fun(pseudo.clone())
}
}
#[inline]
/// Executes a function for each simple (not functional) pseudo-element.
pub fn each_simple_pseudo_element<F>(fun: F)
where F: FnMut(PseudoElement),
{
PseudoElement::each_simple(fun)
}
#[inline]
/// Returns the relevant state flag for a given non-tree-structural
/// pseudo-class.
pub fn pseudo_class_state_flag(pc: &NonTSPseudoClass) -> ElementState {
pc.state_flag()
}
}
fn utf16_to_ascii_lowercase(unit: u16) -> u16 {
match unit {
65...90 => unit + 32, // A-Z => a-z
_ => unit
}
}