servo/components/style/gecko/selector_parser.rs
Emilio Cobos Álvarez fe8da51fee
Bug 1364412: Properly reject to parse pseudo-element states that don't support state. r=bholley
MozReview-Commit-ID: KQCFPtOTGQI
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
2017-05-16 02:53:44 +02:00

391 lines
14 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::{Parser, ToCss};
use element_state::{IN_ACTIVE_STATE, IN_FOCUS_STATE, IN_HOVER_STATE};
use element_state::ElementState;
use gecko_bindings::structs::CSSPseudoClassType;
use selector_parser::{SelectorParser, PseudoElementCascadeType};
use selectors::parser::{ComplexSelector, SelectorMethods};
use selectors::visitor::SelectorVisitor;
use std::borrow::Cow;
use std::fmt;
use string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
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,
}
}
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),)*]) => {
#[doc = "Our representation of a non tree-structural pseudo-class."]
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub enum NonTSPseudoClass {
$(
#[doc = $css]
$name,
)*
$(
#[doc = $s_css]
$s_name(Box<[u16]>),
)*
/// The non-standard `:-moz-any` pseudo-class.
///
/// TODO(emilio): We disallow combinators and pseudos here, so we
/// should use SimpleSelector instead
MozAny(Box<[ComplexSelector<SelectorImpl>]>),
}
}
}
apply_non_ts_list!(pseudo_class_name);
impl ToCss for NonTSPseudoClass {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
use cssparser::CssStringWriter;
use fmt::Write;
macro_rules! pseudo_class_serialize {
(bare: [$(($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),)*]) => {
match *self {
$(NonTSPseudoClass::$name => concat!(":", $css),)*
$(NonTSPseudoClass::$s_name(ref s) => {
write!(dest, ":{}(", $s_css)?;
{
// FIXME(emilio): Avoid the extra allocation!
let mut css = CssStringWriter::new(dest);
// Discount the null char in the end from the
// string.
css.write_str(&String::from_utf16(&s[..s.len() - 1]).unwrap())?;
}
return dest.write_str(")")
}, )*
NonTSPseudoClass::MozAny(ref selectors) => {
dest.write_str(":-moz-any(")?;
let mut iter = selectors.iter();
let first = iter.next().expect(":-moz-any must have at least 1 selector");
first.to_css(dest)?;
for selector in iter {
dest.write_str(", ")?;
selector.to_css(dest)?;
}
return dest.write_str(")")
}
}
}
}
let ser = apply_non_ts_list!(pseudo_class_serialize);
dest.write_str(ser)
}
}
impl SelectorMethods for NonTSPseudoClass {
type Impl = SelectorImpl;
fn visit<V>(&self, visitor: &mut V) -> bool
where V: SelectorVisitor<Impl = Self::Impl>,
{
if let NonTSPseudoClass::MozAny(ref selectors) = *self {
for selector in selectors.iter() {
if !selector.visit(visitor) {
return false;
}
}
}
true
}
}
impl NonTSPseudoClass {
/// A pseudo-class is internal if it can only be used inside
/// user agent style sheets.
pub fn is_internal(&self) -> bool {
macro_rules! check_flag {
(_) => (false);
($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),)*]) => {
match *self {
$(NonTSPseudoClass::$name => check_flag!($flags),)*
$(NonTSPseudoClass::$s_name(..) => check_flag!($s_flags),)*
NonTSPseudoClass::MozAny(_) => false,
}
}
}
apply_non_ts_list!(pseudo_class_check_internal)
}
/// https://drafts.csswg.org/selectors-4/#useraction-pseudos
///
/// We intentionally skip the link-related ones.
fn is_safe_user_action_state(&self) -> bool {
matches!(*self, NonTSPseudoClass::Hover |
NonTSPseudoClass::Active |
NonTSPseudoClass::Focus)
}
/// Get the state flag associated with a pseudo-class, if any.
pub fn state_flag(&self) -> ElementState {
macro_rules! flag {
(_) => (ElementState::empty());
($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),)*]) => {
match *self {
$(NonTSPseudoClass::$name => flag!($state),)*
$(NonTSPseudoClass::$s_name(..) => flag!($s_state),)*
NonTSPseudoClass::MozAny(..) => ElementState::empty(),
}
}
}
apply_non_ts_list!(pseudo_class_state)
}
/// Returns true if the given pseudoclass should trigger style sharing cache revalidation.
pub fn needs_cache_revalidation(&self) -> bool {
self.state_flag().is_empty() &&
!matches!(*self, NonTSPseudoClass::MozAny(_))
}
/// Convert NonTSPseudoClass to Gecko's CSSPseudoClassType.
pub fn to_gecko_pseudoclasstype(&self) -> Option<CSSPseudoClassType> {
macro_rules! gecko_type {
(_) => (None);
($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),)*]) => {
match *self {
$(NonTSPseudoClass::$name => gecko_type!($gecko_type),)*
$(NonTSPseudoClass::$s_name(..) => gecko_type!($s_gecko_type),)*
NonTSPseudoClass::MozAny(_) => gecko_type!(any),
}
}
}
apply_non_ts_list!(pseudo_class_geckotype)
}
}
/// The dummy struct we use to implement our selector parsing.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct SelectorImpl;
/// Some subset of pseudo-elements in Gecko are sensitive to some state
/// selectors.
///
/// We store the sensitive states in this struct in order to properly handle
/// these.
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct PseudoElementSelector {
pseudo: PseudoElement,
state: ElementState,
}
impl PseudoElementSelector {
/// Returns the pseudo-element this selector represents.
pub fn pseudo_element(&self) -> &PseudoElement {
&self.pseudo
}
/// Returns the pseudo-element selector state.
pub fn state(&self) -> ElementState {
self.state
}
}
impl ToCss for PseudoElementSelector {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result
where W: fmt::Write,
{
if cfg!(debug_assertions) {
let mut state = self.state;
state.remove(IN_HOVER_STATE | IN_ACTIVE_STATE | IN_FOCUS_STATE);
assert_eq!(state, ElementState::empty(),
"Unhandled pseudo-element state selector?");
}
self.pseudo.to_css(dest)?;
if self.state.contains(IN_HOVER_STATE) {
dest.write_str(":hover")?
}
if self.state.contains(IN_ACTIVE_STATE) {
dest.write_str(":active")?
}
if self.state.contains(IN_FOCUS_STATE) {
dest.write_str(":focus")?
}
Ok(())
}
}
impl ::selectors::SelectorImpl for SelectorImpl {
type AttrValue = Atom;
type Identifier = Atom;
type ClassName = Atom;
type LocalName = Atom;
type NamespacePrefix = Atom;
type NamespaceUrl = Namespace;
type BorrowedNamespaceUrl = WeakNamespace;
type BorrowedLocalName = WeakAtom;
type PseudoElementSelector = PseudoElementSelector;
type NonTSPseudoClass = NonTSPseudoClass;
}
impl<'a> ::selectors::Parser for SelectorParser<'a> {
type Impl = SelectorImpl;
fn parse_non_ts_pseudo_class(&self, name: Cow<str>) -> Result<NonTSPseudoClass, ()> {
macro_rules! pseudo_class_parse {
(bare: [$(($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),)*]) => {
match_ignore_ascii_case! { &name,
$($css => NonTSPseudoClass::$name,)*
_ => return Err(())
}
}
}
let pseudo_class = apply_non_ts_list!(pseudo_class_parse);
if !pseudo_class.is_internal() || self.in_user_agent_stylesheet() {
Ok(pseudo_class)
} else {
Err(())
}
}
fn parse_non_ts_functional_pseudo_class(&self,
name: Cow<str>,
parser: &mut Parser)
-> Result<NonTSPseudoClass, ()> {
macro_rules! pseudo_class_string_parse {
(bare: [$(($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),)*]) => {
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())
}, )*
"-moz-any" => {
let selectors = parser.parse_comma_separated(|input| {
ComplexSelector::parse(self, input)
})?;
// Selectors inside `:-moz-any` may not include combinators.
if selectors.iter().flat_map(|x| x.iter_raw()).any(|s| s.is_combinator()) {
return Err(())
}
NonTSPseudoClass::MozAny(selectors.into_boxed_slice())
}
_ => return Err(())
}
}
}
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(())
}
}
fn parse_pseudo_element(&self, name: Cow<str>, input: &mut Parser) -> Result<PseudoElementSelector, ()> {
let pseudo =
match PseudoElement::from_slice(&name, self.in_user_agent_stylesheet()) {
Some(pseudo) => pseudo,
None => return Err(()),
};
let state = if pseudo.supports_user_action_state() {
input.try(|input| {
let mut state = ElementState::empty();
while !input.is_exhausted() {
input.expect_colon()?;
let ident = input.expect_ident()?;
let pseudo_class = self.parse_non_ts_pseudo_class(ident)?;
if !pseudo_class.is_safe_user_action_state() {
return Err(())
}
state.insert(pseudo_class.state_flag());
}
Ok(state)
}).ok()
} else {
None
};
Ok(PseudoElementSelector {
pseudo: pseudo,
state: state.unwrap_or(ElementState::empty()),
})
}
fn default_namespace(&self) -> Option<Namespace> {
self.namespaces.default.clone()
}
fn namespace_for_prefix(&self, prefix: &Atom) -> Option<Namespace> {
self.namespaces.prefixes.get(prefix).cloned()
}
}
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 pseudo-element.
pub fn each_pseudo_element<F>(fun: F)
where F: FnMut(PseudoElement),
{
PseudoElement::each(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()
}
}