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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/. */
//! The context within which CSS code is parsed.
use crate::context::QuirksMode;
use crate::error_reporting::{ContextualParseError, ParseErrorReporter};
use crate::stylesheets::{CssRuleType, Namespaces, Origin, UrlExtraData};
use crate::use_counters::UseCounters;
use cssparser::{Parser, SourceLocation, UnicodeRange};
use style_traits::{OneOrMoreSeparated, ParseError, ParsingMode, Separator};
/// Asserts that all ParsingMode flags have a matching ParsingMode value in gecko.
#[cfg(feature = "gecko")]
#[inline]
pub fn assert_parsing_mode_match() {
use crate::gecko_bindings::structs;
macro_rules! check_parsing_modes {
( $( $a:ident => $b:path ),*, ) => {
if cfg!(debug_assertions) {
let mut modes = ParsingMode::all();
$(
assert_eq!(structs::$a as usize, $b.bits() as usize, stringify!($b));
modes.remove($b);
)*
assert_eq!(modes, ParsingMode::empty(), "all ParsingMode bits should have an assertion");
}
}
}
check_parsing_modes! {
ParsingMode_Default => ParsingMode::DEFAULT,
ParsingMode_AllowUnitlessLength => ParsingMode::ALLOW_UNITLESS_LENGTH,
ParsingMode_AllowAllNumericValues => ParsingMode::ALLOW_ALL_NUMERIC_VALUES,
}
}
/// The data that the parser needs from outside in order to parse a stylesheet.
pub struct ParserContext<'a> {
/// The `Origin` of the stylesheet, whether it's a user, author or
/// user-agent stylesheet.
pub stylesheet_origin: Origin,
/// The extra data we need for resolving url values.
pub url_data: &'a UrlExtraData,
/// The current rule type, if any.
pub rule_type: Option<CssRuleType>,
/// The mode to use when parsing.
pub parsing_mode: ParsingMode,
/// The quirks mode of this stylesheet.
pub quirks_mode: QuirksMode,
/// The active error reporter, or none if error reporting is disabled.
error_reporter: Option<&'a dyn ParseErrorReporter>,
/// The currently active namespaces.
pub namespaces: Option<&'a Namespaces>,
/// The use counters we want to record while parsing style rules, if any.
pub use_counters: Option<&'a UseCounters>,
}
impl<'a> ParserContext<'a> {
/// Create a parser context.
#[inline]
pub fn new(
stylesheet_origin: Origin,
url_data: &'a UrlExtraData,
rule_type: Option<CssRuleType>,
parsing_mode: ParsingMode,
quirks_mode: QuirksMode,
error_reporter: Option<&'a dyn ParseErrorReporter>,
use_counters: Option<&'a UseCounters>,
) -> Self {
Self {
stylesheet_origin,
url_data,
rule_type,
parsing_mode,
quirks_mode,
error_reporter,
namespaces: None,
use_counters,
}
}
/// Create a parser context based on a previous context, but with a modified
/// rule type.
#[inline]
pub fn new_with_rule_type(
context: &'a ParserContext,
rule_type: CssRuleType,
namespaces: &'a Namespaces,
) -> ParserContext<'a> {
Self {
stylesheet_origin: context.stylesheet_origin,
url_data: context.url_data,
rule_type: Some(rule_type),
parsing_mode: context.parsing_mode,
quirks_mode: context.quirks_mode,
namespaces: Some(namespaces),
error_reporter: context.error_reporter,
use_counters: context.use_counters,
}
}
/// Whether we're in a @page rule.
#[inline]
pub fn in_page_rule(&self) -> bool {
self.rule_type
.map_or(false, |rule_type| rule_type == CssRuleType::Page)
}
/// Get the rule type, which assumes that one is available.
pub fn rule_type(&self) -> CssRuleType {
self.rule_type
.expect("Rule type expected, but none was found.")
}
/// Returns whether CSS error reporting is enabled.
#[inline]
pub fn error_reporting_enabled(&self) -> bool {
self.error_reporter.is_some()
}
/// Record a CSS parse error with this context’s error reporting.
pub fn log_css_error(&self, location: SourceLocation, error: ContextualParseError) {
let error_reporter = match self.error_reporter {
Some(r) => r,
None => return,
};
error_reporter.report_error(self.url_data, location, error)
}
/// Whether we're in a user-agent stylesheet.
#[inline]
pub fn in_ua_sheet(&self) -> bool {
self.stylesheet_origin == Origin::UserAgent
}
/// Returns whether chrome-only rules should be parsed.
#[inline]
pub fn chrome_rules_enabled(&self) -> bool {
self.url_data.is_chrome() || self.stylesheet_origin == Origin::User
}
/// Whether we're in a user-agent stylesheet or chrome rules are enabled.
#[inline]
pub fn in_ua_or_chrome_sheet(&self) -> bool {
self.in_ua_sheet() || self.chrome_rules_enabled()
}
}
/// A trait to abstract parsing of a specified value given a `ParserContext` and
/// CSS input.
///
/// This can be derived on keywords with `#[derive(Parse)]`.
///
/// The derive code understands the following attributes on each of the variants:
///
/// * `#[parse(aliases = "foo,bar")]` can be used to alias a value with another
/// at parse-time.
///
/// * `#[parse(condition = "function")]` can be used to make the parsing of the
/// value conditional on `function`, which needs to fulfill
/// `fn(&ParserContext) -> bool`.
pub trait Parse: Sized {
/// Parse a value of this type.
///
/// Returns an error on failure.
fn parse<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>>;
}
impl<T> Parse for Vec<T>
where
T: Parse + OneOrMoreSeparated,
<T as OneOrMoreSeparated>::S: Separator,
{
fn parse<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
<T as OneOrMoreSeparated>::S::parse(input, |i| T::parse(context, i))
}
}
impl<T> Parse for Box<T>
where
T: Parse,
{
fn parse<'i, 't>(
context: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
T::parse(context, input).map(Box::new)
}
}
impl Parse for crate::OwnedStr {
fn parse<'i, 't>(
_: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
Ok(input.expect_string()?.as_ref().to_owned().into())
}
}
impl Parse for UnicodeRange {
fn parse<'i, 't>(
_: &ParserContext,
input: &mut Parser<'i, 't>,
) -> Result<Self, ParseError<'i>> {
Ok(UnicodeRange::parse(input)?)
}
}