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a498868ba9
Reviewed by @emilio in [bug 1329088](https://bugzilla.mozilla.org/show_bug.cgi?id=1329088). r? @emilio --- - [x] `./mach build -d` does not report any errors - [x] `./mach test-tidy` does not report any errors Source-Repo: https://github.com/servo/servo Source-Revision: 5c56640508b4f24a67fe92c5d3179d89d030e959 --HG-- extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear extra : subtree_revision : 1f33735051b5be8d58a32eec5044f6365b6dab32
165 lines
6.4 KiB
Rust
165 lines
6.4 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! The context within which CSS code is parsed.
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#![deny(missing_docs)]
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use cssparser::{Parser, SourcePosition, UnicodeRange};
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use error_reporting::ParseErrorReporter;
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use style_traits::OneOrMoreCommaSeparated;
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use stylesheets::{CssRuleType, Origin, UrlExtraData};
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/// The mode to use when parsing lengths.
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#[derive(PartialEq, Eq, Copy, Clone)]
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pub enum LengthParsingMode {
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/// In CSS, lengths must have units, except for zero values, where the unit can be omitted.
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/// https://www.w3.org/TR/css3-values/#lengths
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Default,
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/// In SVG, a coordinate or length value without a unit identifier (e.g., "25") is assumed to be in user units (px).
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/// https://www.w3.org/TR/SVG/coords.html#Units
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SVG,
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}
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impl LengthParsingMode {
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/// Whether the parsing mode allows unitless lengths for non-zero values to be intpreted as px.
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pub fn allows_unitless_lengths(&self) -> bool {
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*self == LengthParsingMode::SVG
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}
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}
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/// The data that the parser needs from outside in order to parse a stylesheet.
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pub struct ParserContext<'a> {
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/// The `Origin` of the stylesheet, whether it's a user, author or
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/// user-agent stylesheet.
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pub stylesheet_origin: Origin,
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/// The extra data we need for resolving url values.
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pub url_data: &'a UrlExtraData,
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/// An error reporter to report syntax errors.
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pub error_reporter: &'a ParseErrorReporter,
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/// The current rule type, if any.
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pub rule_type: Option<CssRuleType>,
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/// Line number offsets for inline stylesheets
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pub line_number_offset: u64,
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/// The mode to use when parsing lengths.
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pub length_parsing_mode: LengthParsingMode,
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}
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impl<'a> ParserContext<'a> {
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/// Create a parser context.
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pub fn new(stylesheet_origin: Origin,
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url_data: &'a UrlExtraData,
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error_reporter: &'a ParseErrorReporter,
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rule_type: Option<CssRuleType>,
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length_parsing_mode: LengthParsingMode)
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-> ParserContext<'a> {
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ParserContext {
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stylesheet_origin: stylesheet_origin,
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url_data: url_data,
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error_reporter: error_reporter,
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rule_type: rule_type,
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line_number_offset: 0u64,
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length_parsing_mode: length_parsing_mode,
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}
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}
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/// Create a parser context for on-the-fly parsing in CSSOM
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pub fn new_for_cssom(url_data: &'a UrlExtraData,
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error_reporter: &'a ParseErrorReporter,
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rule_type: Option<CssRuleType>,
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length_parsing_mode: LengthParsingMode)
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-> ParserContext<'a> {
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Self::new(Origin::Author, url_data, error_reporter, rule_type, length_parsing_mode)
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}
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/// Create a parser context based on a previous context, but with a modified rule type.
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pub fn new_with_rule_type(context: &'a ParserContext,
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rule_type: Option<CssRuleType>)
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-> ParserContext<'a> {
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ParserContext {
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stylesheet_origin: context.stylesheet_origin,
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url_data: context.url_data,
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error_reporter: context.error_reporter,
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rule_type: rule_type,
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line_number_offset: context.line_number_offset,
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length_parsing_mode: context.length_parsing_mode,
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}
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}
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/// Create a parser context for inline CSS which accepts additional line offset argument.
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pub fn new_with_line_number_offset(stylesheet_origin: Origin,
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url_data: &'a UrlExtraData,
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error_reporter: &'a ParseErrorReporter,
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line_number_offset: u64,
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length_parsing_mode: LengthParsingMode)
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-> ParserContext<'a> {
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ParserContext {
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stylesheet_origin: stylesheet_origin,
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url_data: url_data,
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error_reporter: error_reporter,
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rule_type: None,
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line_number_offset: line_number_offset,
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length_parsing_mode: length_parsing_mode,
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}
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}
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/// Get the rule type, which assumes that one is available.
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pub fn rule_type(&self) -> CssRuleType {
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self.rule_type.expect("Rule type expected, but none was found.")
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}
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}
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/// Defaults to a no-op.
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/// Set a `RUST_LOG=style::errors` environment variable
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/// to log CSS parse errors to stderr.
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pub fn log_css_error(input: &mut Parser,
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position: SourcePosition,
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message: &str,
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parsercontext: &ParserContext) {
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let url_data = parsercontext.url_data;
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let line_number_offset = parsercontext.line_number_offset;
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parsercontext.error_reporter.report_error(input, position,
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message, url_data,
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line_number_offset);
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}
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// XXXManishearth Replace all specified value parse impls with impls of this
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// trait. This will make it easy to write more generic values in the future.
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/// A trait to abstract parsing of a specified value given a `ParserContext` and
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/// CSS input.
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pub trait Parse : Sized {
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/// Parse a value of this type.
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///
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/// Returns an error on failure.
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fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ()>;
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}
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impl<T> Parse for Vec<T> where T: Parse + OneOrMoreCommaSeparated {
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fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
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input.parse_comma_separated(|input| T::parse(context, input))
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}
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}
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/// Parse a non-empty space-separated or comma-separated list of objects parsed by parse_one
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pub fn parse_space_or_comma_separated<F, T>(input: &mut Parser, mut parse_one: F)
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-> Result<Vec<T>, ()>
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where F: FnMut(&mut Parser) -> Result<T, ()> {
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let first = parse_one(input)?;
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let mut vec = vec![first];
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loop {
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let _ = input.try(|i| i.expect_comma());
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if let Ok(val) = input.try(|i| parse_one(i)) {
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vec.push(val)
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} else {
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break
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}
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}
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Ok(vec)
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}
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impl Parse for UnicodeRange {
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fn parse(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
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UnicodeRange::parse(input)
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}
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}
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