Revision control
Copy as Markdown
Other Tools
/* 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
use crate::cow_rc_str::CowRcStr;
use crate::tokenizer::{SourceLocation, SourcePosition, Token, Tokenizer};
use smallvec::SmallVec;
use std::fmt;
use std::ops::BitOr;
use std::ops::Range;
/// A capture of the internal state of a `Parser` (including the position within the input),
/// obtained from the `Parser::position` method.
///
/// Can be used with the `Parser::reset` method to restore that state.
/// Should only be used with the `Parser` instance it came from.
#[derive(Debug, Clone)]
pub struct ParserState {
pub(crate) position: usize,
pub(crate) current_line_start_position: usize,
pub(crate) current_line_number: u32,
pub(crate) at_start_of: Option<BlockType>,
}
impl ParserState {
/// The position from the start of the input, counted in UTF-8 bytes.
#[inline]
pub fn position(&self) -> SourcePosition {
SourcePosition(self.position)
}
/// The line number and column number
#[inline]
pub fn source_location(&self) -> SourceLocation {
SourceLocation {
line: self.current_line_number,
column: (self.position - self.current_line_start_position + 1) as u32,
}
}
}
/// When parsing until a given token, sometimes the caller knows that parsing is going to restart
/// at some earlier point, and consuming until we find a top level delimiter is just wasted work.
///
/// In that case, callers can pass ParseUntilErrorBehavior::Stop to avoid doing all that wasted
/// work.
///
/// This is important for things like CSS nesting, where something like:
///
/// foo:is(..) {
/// ...
/// }
///
/// Would need to scan the whole {} block to find a semicolon, only for parsing getting restarted
/// as a qualified rule later.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ParseUntilErrorBehavior {
/// Consume until we see the relevant delimiter or the end of the stream.
Consume,
/// Eagerly error.
Stop,
}
/// Details about a `BasicParseError`
#[derive(Clone, Debug, PartialEq)]
pub enum BasicParseErrorKind<'i> {
/// An unexpected token was encountered.
UnexpectedToken(Token<'i>),
/// The end of the input was encountered unexpectedly.
EndOfInput,
/// An `@` rule was encountered that was invalid.
AtRuleInvalid(CowRcStr<'i>),
/// The body of an '@' rule was invalid.
AtRuleBodyInvalid,
/// A qualified rule was encountered that was invalid.
QualifiedRuleInvalid,
}
impl<'i> fmt::Display for BasicParseErrorKind<'i> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
BasicParseErrorKind::UnexpectedToken(token) => {
write!(f, "unexpected token: {:?}", token)
}
BasicParseErrorKind::EndOfInput => write!(f, "unexpected end of input"),
BasicParseErrorKind::AtRuleInvalid(rule) => {
write!(f, "invalid @ rule encountered: '@{}'", rule)
}
BasicParseErrorKind::AtRuleBodyInvalid => write!(f, "invalid @ rule body encountered"),
BasicParseErrorKind::QualifiedRuleInvalid => {
write!(f, "invalid qualified rule encountered")
}
}
}
}
/// The fundamental parsing errors that can be triggered by built-in parsing routines.
#[derive(Clone, Debug, PartialEq)]
pub struct BasicParseError<'i> {
/// Details of this error
pub kind: BasicParseErrorKind<'i>,
/// Location where this error occurred
pub location: SourceLocation,
}
impl<'i, T> From<BasicParseError<'i>> for ParseError<'i, T> {
#[inline]
fn from(this: BasicParseError<'i>) -> ParseError<'i, T> {
ParseError {
kind: ParseErrorKind::Basic(this.kind),
location: this.location,
}
}
}
impl SourceLocation {
/// Create a new BasicParseError at this location for an unexpected token
#[inline]
pub fn new_basic_unexpected_token_error(self, token: Token<'_>) -> BasicParseError<'_> {
self.new_basic_error(BasicParseErrorKind::UnexpectedToken(token))
}
/// Create a new BasicParseError at this location
#[inline]
pub fn new_basic_error(self, kind: BasicParseErrorKind<'_>) -> BasicParseError<'_> {
BasicParseError {
kind,
location: self,
}
}
/// Create a new ParseError at this location for an unexpected token
#[inline]
pub fn new_unexpected_token_error<E>(self, token: Token<'_>) -> ParseError<'_, E> {
self.new_error(BasicParseErrorKind::UnexpectedToken(token))
}
/// Create a new basic ParseError at the current location
#[inline]
pub fn new_error<E>(self, kind: BasicParseErrorKind<'_>) -> ParseError<'_, E> {
ParseError {
kind: ParseErrorKind::Basic(kind),
location: self,
}
}
/// Create a new custom ParseError at this location
#[inline]
pub fn new_custom_error<'i, E1: Into<E2>, E2>(self, error: E1) -> ParseError<'i, E2> {
ParseError {
kind: ParseErrorKind::Custom(error.into()),
location: self,
}
}
}
/// Details of a `ParseError`
#[derive(Clone, Debug, PartialEq)]
pub enum ParseErrorKind<'i, T: 'i> {
/// A fundamental parse error from a built-in parsing routine.
Basic(BasicParseErrorKind<'i>),
/// A parse error reported by downstream consumer code.
Custom(T),
}
impl<'i, T> ParseErrorKind<'i, T> {
/// Like `std::convert::Into::into`
pub fn into<U>(self) -> ParseErrorKind<'i, U>
where
T: Into<U>,
{
match self {
ParseErrorKind::Basic(basic) => ParseErrorKind::Basic(basic),
ParseErrorKind::Custom(custom) => ParseErrorKind::Custom(custom.into()),
}
}
}
impl<'i, E: fmt::Display> fmt::Display for ParseErrorKind<'i, E> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
ParseErrorKind::Basic(ref basic) => basic.fmt(f),
ParseErrorKind::Custom(ref custom) => custom.fmt(f),
}
}
}
/// Extensible parse errors that can be encountered by client parsing implementations.
#[derive(Clone, Debug, PartialEq)]
pub struct ParseError<'i, E> {
/// Details of this error
pub kind: ParseErrorKind<'i, E>,
/// Location where this error occurred
pub location: SourceLocation,
}
impl<'i, T> ParseError<'i, T> {
/// Extract the fundamental parse error from an extensible error.
pub fn basic(self) -> BasicParseError<'i> {
match self.kind {
ParseErrorKind::Basic(kind) => BasicParseError {
kind,
location: self.location,
},
ParseErrorKind::Custom(_) => panic!("Not a basic parse error"),
}
}
/// Like `std::convert::Into::into`
pub fn into<U>(self) -> ParseError<'i, U>
where
T: Into<U>,
{
ParseError {
kind: self.kind.into(),
location: self.location,
}
}
}
impl<'i, E: fmt::Display> fmt::Display for ParseError<'i, E> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.kind.fmt(f)
}
}
impl<'i, E: fmt::Display + fmt::Debug> std::error::Error for ParseError<'i, E> {}
/// The owned input for a parser.
pub struct ParserInput<'i> {
tokenizer: Tokenizer<'i>,
cached_token: Option<CachedToken<'i>>,
}
struct CachedToken<'i> {
token: Token<'i>,
start_position: SourcePosition,
end_state: ParserState,
}
impl<'i> ParserInput<'i> {
/// Create a new input for a parser.
pub fn new(input: &'i str) -> ParserInput<'i> {
ParserInput {
tokenizer: Tokenizer::new(input),
cached_token: None,
}
}
#[inline]
fn cached_token_ref(&self) -> &Token<'i> {
&self.cached_token.as_ref().unwrap().token
}
}
/// A CSS parser that borrows its `&str` input,
/// yields `Token`s,
/// and keeps track of nested blocks and functions.
pub struct Parser<'i, 't> {
input: &'t mut ParserInput<'i>,
/// If `Some(_)`, .parse_nested_block() can be called.
at_start_of: Option<BlockType>,
/// For parsers from `parse_until` or `parse_nested_block`
stop_before: Delimiters,
}
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub(crate) enum BlockType {
Parenthesis,
SquareBracket,
CurlyBracket,
}
impl BlockType {
fn opening(token: &Token) -> Option<BlockType> {
match *token {
Token::Function(_) | Token::ParenthesisBlock => Some(BlockType::Parenthesis),
Token::SquareBracketBlock => Some(BlockType::SquareBracket),
Token::CurlyBracketBlock => Some(BlockType::CurlyBracket),
_ => None,
}
}
fn closing(token: &Token) -> Option<BlockType> {
match *token {
Token::CloseParenthesis => Some(BlockType::Parenthesis),
Token::CloseSquareBracket => Some(BlockType::SquareBracket),
Token::CloseCurlyBracket => Some(BlockType::CurlyBracket),
_ => None,
}
}
}
/// A set of characters, to be used with the `Parser::parse_until*` methods.
///
/// The union of two sets can be obtained with the `|` operator. Example:
///
/// ```{rust,ignore}
/// input.parse_until_before(Delimiter::CurlyBracketBlock | Delimiter::Semicolon)
/// ```
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub struct Delimiters {
bits: u8,
}
/// `Delimiters` constants.
#[allow(non_upper_case_globals, non_snake_case)]
pub mod Delimiter {
use super::Delimiters;
/// The empty delimiter set
pub const None: Delimiters = Delimiters { bits: 0 };
/// The delimiter set with only the `{` opening curly bracket
pub const CurlyBracketBlock: Delimiters = Delimiters { bits: 1 << 1 };
/// The delimiter set with only the `;` semicolon
pub const Semicolon: Delimiters = Delimiters { bits: 1 << 2 };
/// The delimiter set with only the `!` exclamation point
pub const Bang: Delimiters = Delimiters { bits: 1 << 3 };
/// The delimiter set with only the `,` comma
pub const Comma: Delimiters = Delimiters { bits: 1 << 4 };
}
#[allow(non_upper_case_globals, non_snake_case)]
mod ClosingDelimiter {
use super::Delimiters;
pub const CloseCurlyBracket: Delimiters = Delimiters { bits: 1 << 5 };
pub const CloseSquareBracket: Delimiters = Delimiters { bits: 1 << 6 };
pub const CloseParenthesis: Delimiters = Delimiters { bits: 1 << 7 };
}
impl BitOr<Delimiters> for Delimiters {
type Output = Delimiters;
#[inline]
fn bitor(self, other: Delimiters) -> Delimiters {
Delimiters {
bits: self.bits | other.bits,
}
}
}
impl Delimiters {
#[inline]
fn contains(self, other: Delimiters) -> bool {
(self.bits & other.bits) != 0
}
#[inline]
pub(crate) fn from_byte(byte: Option<u8>) -> Delimiters {
const TABLE: [Delimiters; 256] = {
let mut table = [Delimiter::None; 256];
table[b';' as usize] = Delimiter::Semicolon;
table[b'!' as usize] = Delimiter::Bang;
table[b',' as usize] = Delimiter::Comma;
table[b'{' as usize] = Delimiter::CurlyBracketBlock;
table[b'}' as usize] = ClosingDelimiter::CloseCurlyBracket;
table[b']' as usize] = ClosingDelimiter::CloseSquareBracket;
table[b')' as usize] = ClosingDelimiter::CloseParenthesis;
table
};
match byte {
None => Delimiter::None,
Some(b) => TABLE[b as usize],
}
}
}
/// Used in some `fn expect_*` methods
macro_rules! expect {
($parser: ident, $($branches: tt)+) => {
{
let start_location = $parser.current_source_location();
match *$parser.next()? {
$($branches)+
ref token => {
return Err(start_location.new_basic_unexpected_token_error(token.clone()))
}
}
}
}
}
impl<'i: 't, 't> Parser<'i, 't> {
/// Create a new parser
#[inline]
pub fn new(input: &'t mut ParserInput<'i>) -> Parser<'i, 't> {
Parser {
input,
at_start_of: None,
stop_before: Delimiter::None,
}
}
/// Return the current line that is being parsed.
pub fn current_line(&self) -> &'i str {
self.input.tokenizer.current_source_line()
}
/// Check whether the input is exhausted. That is, if `.next()` would return a token.
///
/// This ignores whitespace and comments.
#[inline]
pub fn is_exhausted(&mut self) -> bool {
self.expect_exhausted().is_ok()
}
/// Check whether the input is exhausted. That is, if `.next()` would return a token.
/// Return a `Result` so that the `?` operator can be used: `input.expect_exhausted()?`
///
/// This ignores whitespace and comments.
#[inline]
pub fn expect_exhausted(&mut self) -> Result<(), BasicParseError<'i>> {
let start = self.state();
let result = match self.next() {
Err(BasicParseError {
kind: BasicParseErrorKind::EndOfInput,
..
}) => Ok(()),
Err(e) => unreachable!("Unexpected error encountered: {:?}", e),
Ok(t) => Err(start
.source_location()
.new_basic_unexpected_token_error(t.clone())),
};
self.reset(&start);
result
}
/// Return the current position within the input.
///
/// This can be used with the `Parser::slice` and `slice_from` methods.
#[inline]
pub fn position(&self) -> SourcePosition {
self.input.tokenizer.position()
}
/// The current line number and column number.
#[inline]
pub fn current_source_location(&self) -> SourceLocation {
self.input.tokenizer.current_source_location()
}
/// The source map URL, if known.
///
/// The source map URL is extracted from a specially formatted
/// comment. The last such comment is used, so this value may
/// change as parsing proceeds.
pub fn current_source_map_url(&self) -> Option<&str> {
self.input.tokenizer.current_source_map_url()
}
/// The source URL, if known.
///
/// The source URL is extracted from a specially formatted
/// comment. The last such comment is used, so this value may
/// change as parsing proceeds.
pub fn current_source_url(&self) -> Option<&str> {
self.input.tokenizer.current_source_url()
}
/// Create a new BasicParseError at the current location
#[inline]
pub fn new_basic_error(&self, kind: BasicParseErrorKind<'i>) -> BasicParseError<'i> {
self.current_source_location().new_basic_error(kind)
}
/// Create a new basic ParseError at the current location
#[inline]
pub fn new_error<E>(&self, kind: BasicParseErrorKind<'i>) -> ParseError<'i, E> {
self.current_source_location().new_error(kind)
}
/// Create a new custom BasicParseError at the current location
#[inline]
pub fn new_custom_error<E1: Into<E2>, E2>(&self, error: E1) -> ParseError<'i, E2> {
self.current_source_location().new_custom_error(error)
}
/// Create a new unexpected token BasicParseError at the current location
#[inline]
pub fn new_basic_unexpected_token_error(&self, token: Token<'i>) -> BasicParseError<'i> {
self.new_basic_error(BasicParseErrorKind::UnexpectedToken(token))
}
/// Create a new unexpected token ParseError at the current location
#[inline]
pub fn new_unexpected_token_error<E>(&self, token: Token<'i>) -> ParseError<'i, E> {
self.new_error(BasicParseErrorKind::UnexpectedToken(token))
}
/// Create a new unexpected token or EOF ParseError at the current location
#[inline]
pub fn new_error_for_next_token<E>(&mut self) -> ParseError<'i, E> {
let token = match self.next() {
Ok(token) => token.clone(),
Err(e) => return e.into(),
};
self.new_error(BasicParseErrorKind::UnexpectedToken(token))
}
/// Return the current internal state of the parser (including position within the input).
///
/// This state can later be restored with the `Parser::reset` method.
#[inline]
pub fn state(&self) -> ParserState {
ParserState {
at_start_of: self.at_start_of,
..self.input.tokenizer.state()
}
}
/// Advance the input until the next token that’s not whitespace or a comment.
#[inline]
pub fn skip_whitespace(&mut self) {
if let Some(block_type) = self.at_start_of.take() {
consume_until_end_of_block(block_type, &mut self.input.tokenizer);
}
self.input.tokenizer.skip_whitespace()
}
#[inline]
pub(crate) fn skip_cdc_and_cdo(&mut self) {
if let Some(block_type) = self.at_start_of.take() {
consume_until_end_of_block(block_type, &mut self.input.tokenizer);
}
self.input.tokenizer.skip_cdc_and_cdo()
}
#[inline]
pub(crate) fn next_byte(&self) -> Option<u8> {
let byte = self.input.tokenizer.next_byte();
if self.stop_before.contains(Delimiters::from_byte(byte)) {
return None;
}
byte
}
/// Restore the internal state of the parser (including position within the input)
/// to what was previously saved by the `Parser::position` method.
///
/// Should only be used with `SourcePosition` values from the same `Parser` instance.
#[inline]
pub fn reset(&mut self, state: &ParserState) {
self.input.tokenizer.reset(state);
self.at_start_of = state.at_start_of;
}
/// Start looking for `var()` / `env()` functions. (See the
/// `.seen_var_or_env_functions()` method.)
#[inline]
pub fn look_for_var_or_env_functions(&mut self) {
self.input.tokenizer.look_for_var_or_env_functions()
}
/// Return whether a `var()` or `env()` function has been seen by the
/// tokenizer since either `look_for_var_or_env_functions` was called, and
/// stop looking.
#[inline]
pub fn seen_var_or_env_functions(&mut self) -> bool {
self.input.tokenizer.seen_var_or_env_functions()
}
/// The old name of `try_parse`, which requires raw identifiers in the Rust 2018 edition.
#[inline]
pub fn r#try<F, T, E>(&mut self, thing: F) -> Result<T, E>
where
F: FnOnce(&mut Parser<'i, 't>) -> Result<T, E>,
{
self.try_parse(thing)
}
/// Execute the given closure, passing it the parser.
/// If the result (returned unchanged) is `Err`,
/// the internal state of the parser (including position within the input)
/// is restored to what it was before the call.
#[inline]
pub fn try_parse<F, T, E>(&mut self, thing: F) -> Result<T, E>
where
F: FnOnce(&mut Parser<'i, 't>) -> Result<T, E>,
{
let start = self.state();
let result = thing(self);
if result.is_err() {
self.reset(&start)
}
result
}
/// Return a slice of the CSS input
#[inline]
pub fn slice(&self, range: Range<SourcePosition>) -> &'i str {
self.input.tokenizer.slice(range)
}
/// Return a slice of the CSS input, from the given position to the current one.
#[inline]
pub fn slice_from(&self, start_position: SourcePosition) -> &'i str {
self.input.tokenizer.slice_from(start_position)
}
/// Return the next token in the input that is neither whitespace or a comment,
/// and advance the position accordingly.
///
/// After returning a `Function`, `ParenthesisBlock`,
/// `CurlyBracketBlock`, or `SquareBracketBlock` token,
/// the next call will skip until after the matching `CloseParenthesis`,
/// `CloseCurlyBracket`, or `CloseSquareBracket` token.
///
/// See the `Parser::parse_nested_block` method to parse the content of functions or blocks.
///
/// This only returns a closing token when it is unmatched (and therefore an error).
#[allow(clippy::should_implement_trait)]
pub fn next(&mut self) -> Result<&Token<'i>, BasicParseError<'i>> {
self.skip_whitespace();
self.next_including_whitespace_and_comments()
}
/// Same as `Parser::next`, but does not skip whitespace tokens.
pub fn next_including_whitespace(&mut self) -> Result<&Token<'i>, BasicParseError<'i>> {
loop {
match self.next_including_whitespace_and_comments() {
Err(e) => return Err(e),
Ok(&Token::Comment(_)) => {}
_ => break,
}
}
Ok(self.input.cached_token_ref())
}
/// Same as `Parser::next`, but does not skip whitespace or comment tokens.
///
/// **Note**: This should only be used in contexts like a CSS pre-processor
/// where comments are preserved.
/// When parsing higher-level values, per the CSS Syntax specification,
/// comments should always be ignored between tokens.
pub fn next_including_whitespace_and_comments(
&mut self,
) -> Result<&Token<'i>, BasicParseError<'i>> {
if let Some(block_type) = self.at_start_of.take() {
consume_until_end_of_block(block_type, &mut self.input.tokenizer);
}
let byte = self.input.tokenizer.next_byte();
if self.stop_before.contains(Delimiters::from_byte(byte)) {
return Err(self.new_basic_error(BasicParseErrorKind::EndOfInput));
}
let token_start_position = self.input.tokenizer.position();
let using_cached_token = self
.input
.cached_token
.as_ref()
.map_or(false, |cached_token| {
cached_token.start_position == token_start_position
});
let token = if using_cached_token {
let cached_token = self.input.cached_token.as_ref().unwrap();
self.input.tokenizer.reset(&cached_token.end_state);
if let Token::Function(ref name) = cached_token.token {
self.input.tokenizer.see_function(name)
}
&cached_token.token
} else {
let new_token = self
.input
.tokenizer
.next()
.map_err(|()| self.new_basic_error(BasicParseErrorKind::EndOfInput))?;
self.input.cached_token = Some(CachedToken {
token: new_token,
start_position: token_start_position,
end_state: self.input.tokenizer.state(),
});
self.input.cached_token_ref()
};
if let Some(block_type) = BlockType::opening(token) {
self.at_start_of = Some(block_type);
}
Ok(token)
}
/// Have the given closure parse something, then check the the input is exhausted.
/// The result is overridden to an `Err(..)` if some input remains.
///
/// This can help tell e.g. `color: green;` from `color: green 4px;`
#[inline]
pub fn parse_entirely<F, T, E>(&mut self, parse: F) -> Result<T, ParseError<'i, E>>
where
F: FnOnce(&mut Parser<'i, 't>) -> Result<T, ParseError<'i, E>>,
{
let result = parse(self)?;
self.expect_exhausted()?;
Ok(result)
}
/// Parse a list of comma-separated values, all with the same syntax.
///
/// The given closure is called repeatedly with a "delimited" parser
/// (see the `Parser::parse_until_before` method) so that it can over
/// consume the input past a comma at this block/function nesting level.
///
/// Successful results are accumulated in a vector.
///
/// This method returns an`Err(..)` the first time that a closure call does,
/// or if a closure call leaves some input before the next comma or the end
/// of the input.
#[inline]
pub fn parse_comma_separated<F, T, E>(
&mut self,
parse_one: F,
) -> Result<Vec<T>, ParseError<'i, E>>
where
F: for<'tt> FnMut(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
self.parse_comma_separated_internal(parse_one, /* ignore_errors = */ false)
}
/// Like `parse_comma_separated`, but ignores errors on unknown components,
/// rather than erroring out in the whole list.
///
/// Caller must deal with the fact that the resulting list might be empty,
/// if there's no valid component on the list.
#[inline]
pub fn parse_comma_separated_ignoring_errors<F, T, E: 'i>(&mut self, parse_one: F) -> Vec<T>
where
F: for<'tt> FnMut(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
match self.parse_comma_separated_internal(parse_one, /* ignore_errors = */ true) {
Ok(values) => values,
Err(..) => unreachable!(),
}
}
#[inline]
fn parse_comma_separated_internal<F, T, E>(
&mut self,
mut parse_one: F,
ignore_errors: bool,
) -> Result<Vec<T>, ParseError<'i, E>>
where
F: for<'tt> FnMut(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
// Vec grows from 0 to 4 by default on first push(). So allocate with
// capacity 1, so in the somewhat common case of only one item we don't
// way overallocate. Note that we always push at least one item if
// parsing succeeds.
let mut values = Vec::with_capacity(1);
loop {
self.skip_whitespace(); // Unnecessary for correctness, but may help try() in parse_one rewind less.
match self.parse_until_before(Delimiter::Comma, &mut parse_one) {
Ok(v) => values.push(v),
Err(e) if !ignore_errors => return Err(e),
Err(_) => {}
}
match self.next() {
Err(_) => return Ok(values),
Ok(&Token::Comma) => continue,
Ok(_) => unreachable!(),
}
}
}
/// Parse the content of a block or function.
///
/// This method panics if the last token yielded by this parser
/// (from one of the `next*` methods)
/// is not a on that marks the start of a block or function:
/// a `Function`, `ParenthesisBlock`, `CurlyBracketBlock`, or `SquareBracketBlock`.
///
/// The given closure is called with a "delimited" parser
/// that stops at the end of the block or function (at the matching closing token).
///
/// The result is overridden to an `Err(..)` if the closure leaves some input before that point.
#[inline]
pub fn parse_nested_block<F, T, E>(&mut self, parse: F) -> Result<T, ParseError<'i, E>>
where
F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
parse_nested_block(self, parse)
}
/// Limit parsing to until a given delimiter or the end of the input. (E.g.
/// a semicolon for a property value.)
///
/// The given closure is called with a "delimited" parser
/// that stops before the first character at this block/function nesting level
/// that matches the given set of delimiters, or at the end of the input.
///
/// The result is overridden to an `Err(..)` if the closure leaves some input before that point.
#[inline]
pub fn parse_until_before<F, T, E>(
&mut self,
delimiters: Delimiters,
parse: F,
) -> Result<T, ParseError<'i, E>>
where
F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
parse_until_before(self, delimiters, ParseUntilErrorBehavior::Consume, parse)
}
/// Like `parse_until_before`, but also consume the delimiter token.
///
/// This can be useful when you don’t need to know which delimiter it was
/// (e.g. if these is only one in the given set)
/// or if it was there at all (as opposed to reaching the end of the input).
#[inline]
pub fn parse_until_after<F, T, E>(
&mut self,
delimiters: Delimiters,
parse: F,
) -> Result<T, ParseError<'i, E>>
where
F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
parse_until_after(self, delimiters, ParseUntilErrorBehavior::Consume, parse)
}
/// Parse a <whitespace-token> and return its value.
#[inline]
pub fn expect_whitespace(&mut self) -> Result<&'i str, BasicParseError<'i>> {
let start_location = self.current_source_location();
match *self.next_including_whitespace()? {
Token::WhiteSpace(value) => Ok(value),
ref t => Err(start_location.new_basic_unexpected_token_error(t.clone())),
}
}
/// Parse a <ident-token> and return the unescaped value.
#[inline]
pub fn expect_ident(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
expect! {self,
Token::Ident(ref value) => Ok(value),
}
}
/// expect_ident, but clone the CowRcStr
#[inline]
pub fn expect_ident_cloned(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
self.expect_ident().cloned()
}
/// Parse a <ident-token> whose unescaped value is an ASCII-insensitive match for the given value.
#[inline]
pub fn expect_ident_matching(
&mut self,
expected_value: &str,
) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::Ident(ref value) if value.eq_ignore_ascii_case(expected_value) => Ok(()),
}
}
/// Parse a <string-token> and return the unescaped value.
#[inline]
pub fn expect_string(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
expect! {self,
Token::QuotedString(ref value) => Ok(value),
}
}
/// expect_string, but clone the CowRcStr
#[inline]
pub fn expect_string_cloned(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
self.expect_string().cloned()
}
/// Parse either a <ident-token> or a <string-token>, and return the unescaped value.
#[inline]
pub fn expect_ident_or_string(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
expect! {self,
Token::Ident(ref value) => Ok(value),
Token::QuotedString(ref value) => Ok(value),
}
}
/// Parse a <url-token> and return the unescaped value.
#[inline]
pub fn expect_url(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
expect! {self,
Token::UnquotedUrl(ref value) => Ok(value.clone()),
Token::Function(ref name) if name.eq_ignore_ascii_case("url") => {
self.parse_nested_block(|input| {
input.expect_string().map_err(Into::into).cloned()
})
.map_err(ParseError::<()>::basic)
}
}
}
/// Parse either a <url-token> or a <string-token>, and return the unescaped value.
#[inline]
pub fn expect_url_or_string(&mut self) -> Result<CowRcStr<'i>, BasicParseError<'i>> {
expect! {self,
Token::UnquotedUrl(ref value) => Ok(value.clone()),
Token::QuotedString(ref value) => Ok(value.clone()),
Token::Function(ref name) if name.eq_ignore_ascii_case("url") => {
self.parse_nested_block(|input| {
input.expect_string().map_err(Into::into).cloned()
})
.map_err(ParseError::<()>::basic)
}
}
}
/// Parse a <number-token> and return the integer value.
#[inline]
pub fn expect_number(&mut self) -> Result<f32, BasicParseError<'i>> {
expect! {self,
Token::Number { value, .. } => Ok(value),
}
}
/// Parse a <number-token> that does not have a fractional part, and return the integer value.
#[inline]
pub fn expect_integer(&mut self) -> Result<i32, BasicParseError<'i>> {
expect! {self,
Token::Number { int_value: Some(int_value), .. } => Ok(int_value),
}
}
/// Parse a <percentage-token> and return the value.
/// `0%` and `100%` map to `0.0` and `1.0` (not `100.0`), respectively.
#[inline]
pub fn expect_percentage(&mut self) -> Result<f32, BasicParseError<'i>> {
expect! {self,
Token::Percentage { unit_value, .. } => Ok(unit_value),
}
}
/// Parse a `:` <colon-token>.
#[inline]
pub fn expect_colon(&mut self) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::Colon => Ok(()),
}
}
/// Parse a `;` <semicolon-token>.
#[inline]
pub fn expect_semicolon(&mut self) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::Semicolon => Ok(()),
}
}
/// Parse a `,` <comma-token>.
#[inline]
pub fn expect_comma(&mut self) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::Comma => Ok(()),
}
}
/// Parse a <delim-token> with the given value.
#[inline]
pub fn expect_delim(&mut self, expected_value: char) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::Delim(value) if value == expected_value => Ok(()),
}
}
/// Parse a `{ /* ... */ }` curly brackets block.
///
/// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
#[inline]
pub fn expect_curly_bracket_block(&mut self) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::CurlyBracketBlock => Ok(()),
}
}
/// Parse a `[ /* ... */ ]` square brackets block.
///
/// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
#[inline]
pub fn expect_square_bracket_block(&mut self) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::SquareBracketBlock => Ok(()),
}
}
/// Parse a `( /* ... */ )` parenthesis block.
///
/// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
#[inline]
pub fn expect_parenthesis_block(&mut self) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::ParenthesisBlock => Ok(()),
}
}
/// Parse a <function> token and return its name.
///
/// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
#[inline]
pub fn expect_function(&mut self) -> Result<&CowRcStr<'i>, BasicParseError<'i>> {
expect! {self,
Token::Function(ref name) => Ok(name),
}
}
/// Parse a <function> token whose name is an ASCII-insensitive match for the given value.
///
/// If the result is `Ok`, you can then call the `Parser::parse_nested_block` method.
#[inline]
pub fn expect_function_matching(
&mut self,
expected_name: &str,
) -> Result<(), BasicParseError<'i>> {
expect! {self,
Token::Function(ref name) if name.eq_ignore_ascii_case(expected_name) => Ok(()),
}
}
/// Parse the input until exhaustion and check that it contains no “error” token.
///
/// See `Token::is_parse_error`. This also checks nested blocks and functions recursively.
#[inline]
pub fn expect_no_error_token(&mut self) -> Result<(), BasicParseError<'i>> {
loop {
match self.next_including_whitespace_and_comments() {
Ok(&Token::Function(_))
| Ok(&Token::ParenthesisBlock)
| Ok(&Token::SquareBracketBlock)
| Ok(&Token::CurlyBracketBlock) => self
.parse_nested_block(|input| input.expect_no_error_token().map_err(Into::into))
.map_err(ParseError::<()>::basic)?,
Ok(t) => {
// FIXME: maybe these should be separate variants of
// BasicParseError instead?
if t.is_parse_error() {
let token = t.clone();
return Err(self.new_basic_unexpected_token_error(token));
}
}
Err(_) => return Ok(()),
}
}
}
}
pub fn parse_until_before<'i: 't, 't, F, T, E>(
parser: &mut Parser<'i, 't>,
delimiters: Delimiters,
error_behavior: ParseUntilErrorBehavior,
parse: F,
) -> Result<T, ParseError<'i, E>>
where
F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
let delimiters = parser.stop_before | delimiters;
let result;
// Introduce a new scope to limit duration of nested_parser’s borrow
{
let mut delimited_parser = Parser {
input: parser.input,
at_start_of: parser.at_start_of.take(),
stop_before: delimiters,
};
result = delimited_parser.parse_entirely(parse);
if error_behavior == ParseUntilErrorBehavior::Stop && result.is_err() {
return result;
}
if let Some(block_type) = delimited_parser.at_start_of {
consume_until_end_of_block(block_type, &mut delimited_parser.input.tokenizer);
}
}
// FIXME: have a special-purpose tokenizer method for this that does less work.
loop {
if delimiters.contains(Delimiters::from_byte(parser.input.tokenizer.next_byte())) {
break;
}
if let Ok(token) = parser.input.tokenizer.next() {
if let Some(block_type) = BlockType::opening(&token) {
consume_until_end_of_block(block_type, &mut parser.input.tokenizer);
}
} else {
break;
}
}
result
}
pub fn parse_until_after<'i: 't, 't, F, T, E>(
parser: &mut Parser<'i, 't>,
delimiters: Delimiters,
error_behavior: ParseUntilErrorBehavior,
parse: F,
) -> Result<T, ParseError<'i, E>>
where
F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
let result = parse_until_before(parser, delimiters, error_behavior, parse);
if error_behavior == ParseUntilErrorBehavior::Stop && result.is_err() {
return result;
}
let next_byte = parser.input.tokenizer.next_byte();
if next_byte.is_some()
&& !parser
.stop_before
.contains(Delimiters::from_byte(next_byte))
{
debug_assert!(delimiters.contains(Delimiters::from_byte(next_byte)));
// We know this byte is ASCII.
parser.input.tokenizer.advance(1);
if next_byte == Some(b'{') {
consume_until_end_of_block(BlockType::CurlyBracket, &mut parser.input.tokenizer);
}
}
result
}
pub fn parse_nested_block<'i: 't, 't, F, T, E>(
parser: &mut Parser<'i, 't>,
parse: F,
) -> Result<T, ParseError<'i, E>>
where
F: for<'tt> FnOnce(&mut Parser<'i, 'tt>) -> Result<T, ParseError<'i, E>>,
{
let block_type = parser.at_start_of.take().expect(
"\
A nested parser can only be created when a Function, \
ParenthesisBlock, SquareBracketBlock, or CurlyBracketBlock \
token was just consumed.\
",
);
let closing_delimiter = match block_type {
BlockType::CurlyBracket => ClosingDelimiter::CloseCurlyBracket,
BlockType::SquareBracket => ClosingDelimiter::CloseSquareBracket,
BlockType::Parenthesis => ClosingDelimiter::CloseParenthesis,
};
let result;
// Introduce a new scope to limit duration of nested_parser’s borrow
{
let mut nested_parser = Parser {
input: parser.input,
at_start_of: None,
stop_before: closing_delimiter,
};
result = nested_parser.parse_entirely(parse);
if let Some(block_type) = nested_parser.at_start_of {
consume_until_end_of_block(block_type, &mut nested_parser.input.tokenizer);
}
}
consume_until_end_of_block(block_type, &mut parser.input.tokenizer);
result
}
#[inline(never)]
#[cold]
fn consume_until_end_of_block(block_type: BlockType, tokenizer: &mut Tokenizer) {
let mut stack = SmallVec::<[BlockType; 16]>::new();
stack.push(block_type);
// FIXME: have a special-purpose tokenizer method for this that does less work.
while let Ok(ref token) = tokenizer.next() {
if let Some(b) = BlockType::closing(token) {
if *stack.last().unwrap() == b {
stack.pop();
if stack.is_empty() {
return;
}
}
}
if let Some(block_type) = BlockType::opening(token) {
stack.push(block_type);
}
}
}